Device for driving liquid to rotate by laser

Abstract

The invention discloses a device for driving liquid to rotate by laser, which comprises a container, a metal substrate, a convex lens and a laser, the container is provided with a cavity for containing the liquid, the cavity comprises an annular flow channel and a straight flow channel, the straight flow channel is located in the tangential direction of the annular flow channel and is communicated with the annular flow channel, and the convex lens is arranged on the metal substrate. The metal substrate blocks the inlet end of the straight flow channel, and light emitted by the laser is focused by the convex lens and then irradiates the metal substrate so as to drive liquid to move. According to the invention, the metal substrate receives the energy of the laser to generate the power for the flowing of the liquid in the cavity, and the cavity converts the flowing path of the liquid through the cooperative use of the straight flow channel and the annular flow channel, so that the long-range and stable liquid circulation driven by the laser can be realized, and the long-range property and the stability of the linear motion are well kept; and the flow velocity of the liquid in the cavity can be controlled by controlling the power of the input laser, the controllability is high, the flexibility is higher, and the application cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of optically controlled flow, and in particular to a device for driving liquid rotation by laser. Background Art

[0002] Optical flow control technology has a large number of applications in microfluidic systems, basic research in biology and chemistry, and medical devices. The use of light to drive fluids has excellent characteristics such as no energy loss, no contact and no pollution, and easy and precise control in time and space. Since photons have linear momentum and mechanical kinetic energy, lasers are widely used in this field due to their significant advantages of high intensity, high directionality and monochromaticity. Transferring the momentum of lasers to fluids and controlling fluids efficiently and accurately has been a research hotspot in recent decades. There are currently four main methods used to achieve optical flow control:

[0003] Optical momentum drive. The optical momentum is used to generate deformation and control the fluid. The laser beam is irradiated on the interface of two immiscible liquids with different refractive indices, and the optical radiation pressure is generated to cause the liquid surface between the two liquid surfaces to deform, that is, the interface is distorted toward the side with the lower refractive index of the two liquids. Optical tweezers technology is also one of them.

[0004] Photothermal drive. The photothermal effect is used to locally change the surface tension of the liquid surface and thus control the fluid. When the laser is irradiated at the interface between two liquids, the temperature of the irradiated part rises. The temperature increase will cause the density of liquid molecules to decrease, resulting in a significant difference in the surface tension of the two liquid surfaces, and then forming a surface tension gradient, causing the liquid to flow from the area with high surface tension to the area with low surface tension, forming the Marangoni effect.

[0005] Light modulates voltage to drive fluid. Control is achieved by integrating photoconductive materials under the electrowetting electrode, that is, a charged tiny droplet is attached to an electrode covered with an optically conductive medium. By changing the laser irradiation conditions, the conductivity of the medium itself will change, which will lead to a change in the potential difference, so that the attachment angle of the tiny droplet will become smaller, which can drive the droplet to move.

[0006] Photo-induced ultrasound drives fluid movement. In 2017, researchers irradiated a 527nm pulsed laser into a cuvette filled with a gold nano-solution, focused the laser on the front surface of the cuvette, and after a few minutes or ten minutes of processing time, a strong straight jet could be observed on the surface of the cuvette where the laser was incident through a CCD camera. The maximum jet could reach 4cm / s. Injecting gold nanoparticles into the four walls of the cuvette or attaching a glass substrate coated with a nano-gold layer to the four walls of the cuvette can also produce a strong straight jet at the laser incident point. This is because gold has an absorption peak near 527nm. When a laser with a wavelength near the absorption peak on the metal spectrum is irradiated on the metal, the metal undergoes a surface plasmon resonance effect. The surface plasmon resonance effect absorbs a large amount of laser light and then partially converts it into ultrasonic waves, which then pushes the fluid to make a directional motion perpendicular to the surface of the cuvette. The ultrasonic signal detector placed in the solution also successfully detected the ultrasonic signal. However, this light-controlled fluid solution can only control the linear motion of the fluid, while the light-controlled fluid rotational motion is still a difficulty. Since the rotational motion of fluid has important applications in the field of microfluidic control, it is necessary to develop a light-controlled fluid rotation solution with simple equipment and low cost. Summary of the invention

[0007] The purpose of the present invention is to provide a laser-driven liquid rotation device to address the problem that the existing photo-ultrasonic driven fluid motion is all linear motion and laser-driven fluid rotation or circulation cannot be achieved. The device can convert the laser-driven liquid linear motion into circular motion and can control the flow rate of the liquid in the cavity by controlling the power of the input laser.

[0008] The present invention is achieved through the following technical solutions:

[0009] The present invention provides a device for laser-driven liquid rotation, comprising a container, a metal substrate, a convex lens and a laser, wherein the container has a cavity for containing liquid, the cavity comprises an annular flow channel and a straight flow channel, the straight flow channel is located in the tangential direction of the annular flow channel and penetrates therewith, the metal substrate is sealed at the inlet end of the straight flow channel, and the light emitted by the laser is focused by the convex lens and then irradiated onto the metal substrate to drive the movement of the liquid.

[0010] In the above scheme, the cavity composed of the straight flow channel and the annular flow channel is used to hold the liquid driven by the laser, and the flow state of the liquid is converted into rotation. The metal substrate is placed at the inlet end of the straight flow channel (i.e., the end of the straight flow channel that is not tangent to the annular flow channel) to receive the energy of the laser and generate power for the liquid to flow in the cavity. The above cavity converts the flow path of the liquid through the coordinated use of the straight flow channel and the annular flow channel, which can realize the long-range and stable liquid circulation driven by the laser, and well retains the long-range and stability of the linear motion.

[0011] As a preferred solution of the present invention, the metal substrate includes a quartz substrate injected with gold ions or a glass substrate plated with a 200-500 nm gold layer.

[0012] As a preferred embodiment of the present invention, the liquid includes deionized water or a gold nanoparticle solution.

[0013] As a preferred solution of the present invention, fluorescent particles are added to the liquid to increase the color of the laser path.

[0014] As a preferred embodiment of the present invention, the cross-sectional shape of the straight flow channel is the same as that of the annular flow channel, and the length of the straight flow channel is slightly smaller than the radius of the outer boundary of the annular flow channel.

[0015] As a preferred solution of the present invention, the cross section of the annular flow channel is rectangular, and the width in the radial direction is 30-40 mm.

[0016] As a preferred solution of the present invention, the container is disc-shaped, and a portion of the top surface of the container is recessed downward to form the cavity.

[0017] As a preferred solution of the present invention, a notch is provided on the side wall of the container at a position opposite to the inlet end of the straight flow channel, and the metal substrate is placed in the notch to block the inlet end of the straight flow channel.

[0018] As a preferred solution of the present invention, the metal substrate is perpendicular to the central axis of the straight channel, and the light emitted by the laser is focused and irradiated at the intersection of the central axis of the straight channel and the metal substrate.

[0019] As a preferred solution of the present invention, the wavelength of the laser is 520-550 nm, and the power of the laser is 100-500 mW.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] 1. The present invention realizes the long-range and stable liquid circulation driven by laser for the first time. By setting straight flow channels and annular flow channels, the flow path of the liquid is converted, and the long-range and stability of the linear motion are well preserved;

[0022] 2. The control source of the present invention is single, and the control accuracy is high. Apart from the laser as the control source, no other physical field needs to be added, and the requirements for the experimental environment are low. The small number of control sources also makes the results unaffected by other redundant conditions, and is only strictly related to the laser power, and has strong controllability;

[0023] 3. The present invention is non-contact and does not require any external rotating shaft, wires, etc. The laser source can also be remotely controlled without direct contact with the equipment, which is more flexible;

[0024] 4. The present invention has a regular structure and is easy to process. The entire cavity is composed of two regular structures. Traditional turning and milling processes can meet the processing and production conditions, and the application cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0026] Figure 1 This is a schematic diagram of a top view of a device for laser-driven liquid rotation in the present invention;

[0027] Figure 2 For the present invention Figure 1 AA cutaway diagram of the container in FIG.

[0028] Figure 3 For the present invention Figure 1 Schematic diagram of the three-dimensional state of the container;

[0029] Figure 4 The experimental results of the laser-driven liquid linear jet in the present invention;

[0030] Figure 5 This is a schematic diagram of the laser-driven liquid rotation state in the present invention;

[0031] Figure 6 The flow field conditions simulated by the present invention in COMSOL finite element simulation software;

[0032] Figure 7 This is a curve showing the relationship between the driving laser power and the liquid rotation velocity used in the present invention.

[0033] Marks and corresponding parts names in the attached drawings:

[0034] 1-container, 11-annular flow channel, 12-straight flow channel, 2-metal substrate, 3-laser, 4-convex lens. DETAILED DESCRIPTION

[0035] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0037] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0038] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0039] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0040] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0041] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces), unless otherwise clearly and specifically defined.

[0042] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0043] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0044] Please refer to Figures 1 to 7 A laser-driven liquid rotation device provided in an embodiment of the present application includes a container 1, a metal substrate 2, a laser 3 and a convex lens 4. The container 1 has a cavity for holding liquid, and the cavity includes an annular flow channel 11 and a straight flow channel 12. The straight flow channel 12 is located in the tangential direction of the annular flow channel 11 and penetrates therewith. The metal substrate 2 is sealed at the inlet end of the straight flow channel 12. The light emitted by the laser 3 is focused by the convex lens 4 and irradiated on the metal substrate 2 to drive the movement of the liquid.

[0045] In this embodiment, a cavity formed by the tangent straight channel 12 and the annular channel 11 is used to hold the liquid driven by the laser, and the flow state of the liquid is converted into rotation. The metal substrate 2 is placed at the inlet end of the straight channel 12 (i.e., the end of the straight channel 12 that is not tangent to the annular channel 11) to receive the energy of the laser and generate power for the liquid to flow in the cavity. The above-mentioned cavity converts the flow path of the liquid through the coordinated use of the straight channel 12 and the annular channel 11, which can realize long-range and stable liquid circulation driven by laser, and well retains the long-range and stability of the linear motion.

[0046] Specifically, after the metal substrate 2 is irradiated by the laser, the converted energy can drive the liquid to flow in a straight line in the straight flow channel 12, so that part of the liquid enters the annular flow channel 11, and part of the liquid returns and is driven by the energy of the laser again to form a small vortex in the straight flow channel 12, thereby driving the liquid in the cavity to form a circulation.

[0047] According to some embodiments of the present application, the metal substrate 2 can be a quartz substrate injected with gold ions or a glass substrate plated with a 200-500nm gold layer, wherein the gold nanoparticles are used to convert the energy of the laser to drive the liquid to move. Both of the above two metal substrates 2 can realize real-time driving of the laser convection field.

[0048] According to some embodiments of the present application, the liquid may be deionized water or a gold nanoparticle solution. In order to better achieve the flow phenomenon, the above two liquids may be used, which can reduce influencing factors. It should be noted that the container 1 for holding the liquid should not be made of a particularly hydrophilic or hydrophobic material, and the exemplary container 1 may be made of a resin material or a glass material, or other materials that meet the requirements.

[0049] According to some embodiments of the present application, fluorescent particles are added to the liquid to increase the color of the laser path, which can facilitate observation during the experiment.

[0050] According to some embodiments of the present application, the cross-sectional shape of the straight flow channel 12 is the same as the cross-sectional shape of the annular flow channel 11, and the length L of the straight flow channel 12 is slightly smaller than the radius R of the outer boundary of the annular flow channel 11. By controlling the cross-sectional shape and length of the straight flow channel 12, since the metal substrate 2 is close to the annular flow channel 11, after the metal substrate 2 is irradiated by the laser, the energy converted by the metal substrate 2 can drive the liquid to flow in a straight line in the straight flow channel 12, and make part of the liquid enter the annular flow channel 11, and form a small vortex. When the length L of the straight flow channel 12 is too long, the metal substrate 2 is far away from the annular flow channel 11. At this time, the energy converted by the metal substrate 2 cannot drive part of the liquid into the annular flow channel 11, nor can it form a small vortex, which is not conducive to achieving liquid circulation.

[0051] According to some embodiments of the present application, the cross section of the annular flow channel 11 is rectangular, and the width in the radial direction is 30-40 mm. By designing the cross section of the annular flow channel 11 to be rectangular, such a regular cross-sectional shape is adopted, so that the annular flow channel 11 is conveniently manufactured on the container 1.

[0052] According to some embodiments of the present application, the container 1 is disc-shaped, and a portion of the top surface of the container 1 is recessed downward to form the cavity. After adopting the above solution, the top of the cavity coincides with the top surface of the container 1, that is, the top of the cavity is open, so that the straight flow channel 12 and the annular flow channel 11 can be directly machined by turning and milling technology.

[0053] According to some embodiments of the present application, a notch is provided on the side wall of the container 1 at a position opposite to the inlet end of the straight flow channel 12, and the metal substrate 2 is placed in the notch to block the inlet end of the straight flow channel 12. By designing the notch on the side wall of the container 1, it is convenient to install and fix the metal substrate 2 at the inlet end of the straight flow channel 12.

[0054] According to some embodiments of the present application, the metal substrate 2 is perpendicular to the central axis of the straight flow channel 12, and the light emitted by the laser 3 is focused and irradiated at the intersection of the central axis of the straight flow channel 12 and the metal substrate 2. By adopting the above technical solution, the effect of laser-driven liquid circulation is improved.

[0055] According to some embodiments of the present application, the wavelength of the laser 3 is 520-550 nm, and the power of the laser 3 is 100-500 mW.

[0056] Specifically, this embodiment uses a 532nm semiconductor laser as a control source, and other green lasers with a wavelength near 527nm can also be used. The power is controllable between 0 and 500 milliwatts. The liquid is deionized water. The metal substrate 2 used to convert laser energy is a 2mm transparent glass substrate coated with a 300nm gold layer for related experiments.

[0057] Figure 4 The laser-driven straight-line flow of liquid in a common rectangular container 1 is demonstrated when the laser is incident on the metal substrate 2. A long-range and stable straight-line jet can be seen under the color development function of the fluorescent particles. When the laser power is 200 milliwatts, the jet speed is about 4 cm / s. This also proves that the metal substrate 2 can realize the driving function.

[0058] Figure 5 The laser-driven liquid rotation state in this embodiment is shown. The light emitted by the 532nm laser 3 is focused by the convex lens 4 and irradiated on the metal substrate 2. The energy converted by the metal substrate 2 first drives the liquid to flow in a straight line in the straight channel 12. When the flow state reaches the annular channel 11, the liquid is subject to greater resistance, part of the liquid enters the bend, and part of the liquid returns. The returned liquid is again driven by the energy of the laser to form a small vortex in the straight channel 12. The small vortex formed will also become the driving force for the liquid in the entire cavity to flow in the same direction, promoting the large circulation in the annular channel 11.

[0059] Figure 6 The flow field in the cavity under the same conditions as in the present embodiment is simulated in COMSOL finite element simulation software. A small eddy current can be observed at the laser incident position, which further leads to a large circulation in the entire cavity, further verifying the correctness of the above explanation.

[0060] Figure 7 The relationship curve between the driving laser power used in this embodiment and the liquid rotation flow rate is shown. It can be found that the laser power is basically positively correlated with the liquid rotation flow rate. This relationship diagram can be used to accurately control the flow rate.

[0061] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A laser-driven liquid rotation device, characterized in that: The invention comprises a container, a metal substrate, a convex lens and a laser. The container has a cavity for containing liquid. The cavity comprises an annular flow channel and a straight flow channel. The straight flow channel is located in the tangent direction of the annular flow channel and penetrates the annular flow channel. The metal substrate is sealed at the inlet end of the straight flow channel. The light emitted by the laser is focused by the convex lens and irradiated onto the metal substrate to drive the movement of the liquid.

2. The laser-driven liquid rotation device according to claim 1, characterized in that: The metal substrate includes a quartz substrate injected with gold ions or a glass substrate plated with a 200-500nm gold layer.

3. The laser-driven liquid rotation device according to claim 1, characterized in that: The liquid includes deionized water or a gold nanoparticle solution.

4. The laser-driven liquid rotation device according to claim 3, characterized in that: Fluorescent particles are added to the liquid to increase the color of the laser path.

5. The laser-driven liquid rotation device according to claim 1, characterized in that: The cross-sectional shape of the straight flow channel is the same as the cross-sectional shape of the annular flow channel, and the length of the straight flow channel is slightly smaller than the radius value of the outer boundary of the annular flow channel.

6. The laser-driven liquid rotation device according to claim 5, characterized in that: The cross section of the annular flow channel is rectangular, and the width in the radial direction is 30-40 mm.

7. The laser-driven liquid rotation device according to claim 1, characterized in that: The container is in a disc shape, and a portion of the top surface of the container is recessed downward to form the cavity.

8. The laser-driven liquid rotation device according to claim 7, characterized in that: A notch is provided on the side wall of the container at a position opposite to the inlet end of the straight flow channel, and the metal substrate is placed in the notch to block the inlet end of the straight flow channel.

9. The laser-driven liquid rotation device according to claim 1, characterized in that: The metal substrate is perpendicular to the central axis of the straight flow channel, and the light emitted by the laser is focused and irradiated at the intersection of the central axis of the straight flow channel and the metal substrate.

10. The laser-driven liquid rotation device according to claim 1, characterized in that: The wavelength of the laser is 520-550 nm, and the power of the laser is 100-500 mW.

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