A device for driving a liquid in rotation by means of a laser

Abstract

The application discloses a device for driving liquid rotation by laser, which 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 through the annular flow channel, the metal substrate is blocked 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 on the metal substrate to drive the liquid movement. In the application, the metal substrate receives the energy of the laser to generate the power of the liquid flow in the cavity. The cooperation of the straight flow channel and the annular flow channel converts the flow path of the liquid, the laser can drive the long-range and stable liquid circulation, the long-range and stability of the linear motion are well reserved, the flow rate 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 present application relates to the field of light-controlled flow technology, and particularly relates to a device for driving liquid rotation by laser. BACKGROUND

[0002] Light-controlled flow technology has a large number of applications in microfluidic systems, biology, chemical basic research and medical devices. Using light to drive fluid has the advantages of no energy loss, no contact and no pollution, and easy accurate control in time and space. Since photons have linear momentum and mechanical energy, laser is widely used in this field due to its high intensity, high directionality and monochromaticity. The transmission of laser momentum to fluid and the efficient and accurate control of fluid have been the focus of research in recent decades. There are mainly four methods to achieve light-controlled flow at present:

[0003] Light momentum driving. The deformation is generated by light momentum to control the fluid. The laser beam is irradiated on the interface of two liquids with different refractive indexes and mutually insoluble, and the optical radiation pressure is generated to cause the liquid surface distortion between the two liquid surfaces, that is, the interface is distorted to the side with lower refractive index of the two liquids. The light tweezers technology is also one of them.

[0004] Light-thermal driving. The surface tension of the liquid surface is locally changed by light-thermal effect to control the fluid. When the laser is irradiated on the interface of two liquids, the temperature of the irradiated part is increased. The increase of temperature will cause the decrease of liquid molecular density, so that the surface tension of the two liquid surfaces will be obviously different, and then the surface tension difference gradient is formed, which causes the liquid to flow from the place with high surface tension to the place with low surface tension, forming the Malingani effect.

[0005] Light-modulated voltage driving fluid. The control is realized by integrating photoconductive material under the electrowetting electrode, that is, a small charged droplet is attached to the electrode covered with optical conductive medium. By changing the irradiation of the laser, the conductivity of the medium itself will change, and then the potential difference will change, so that the attachment angle of the small droplet will be small, which can drive the droplet to move.

[0006] Light-induced ultrasonic drives fluid movement. In 2017, researchers by 527nm pulsed laser irradiation into the cuvette filled with gold nanometer solution, the laser is focused on the front surface of the cuvette, after a few minutes or ten minutes of processing time, by CCD camera can be observed in the laser injection of the cuvette surface strong linear jet, jet can reach a maximum of 4cm / s. The four walls of the cuvette are injected with gold nanoparticles or the glass substrate plated with a layer of gold nanoparticles is attached to the four walls of the cuvette, the same can be generated in the laser injection place strong linear jet. This is due to the existence of absorption peak near 527nm of gold, when the laser of wavelength near the absorption peak on the metal spectrum is irradiated on the metal, the metal surface plasmon resonance effect occurs, the surface plasmon resonance effect absorbs a large amount of laser and then partially converts into ultrasonic wave, then pushes the fluid to do the directional motion perpendicular to the surface of the cuvette, the ultrasonic signal detector placed in the solution also successfully detects the ultrasonic signal. But this light-controlled fluid scheme can only control the linear motion of the fluid, and the light-controlled fluid rotation is still a difficulty. Since the rotational motion of the fluid has important application in the field of microfluidic control, it is necessary to develop a simple and low-cost light-controlled fluid rotation scheme. SUMMARY

[0007] The present application aims at: for the problem that the existing light-induced ultrasonic drives fluid movement is linear motion, and it is still unable to realize laser driving fluid rotation or circulation, providing a device for laser driving liquid rotation, which can convert the linear motion of laser driving liquid into circular motion, and can control the flow rate of liquid in the cavity by controlling the power of input laser.

[0008] The present application is realized by the following technical scheme:

[0009] The present application provides a device for laser driving liquid rotation, comprising a container, a metal substrate, a convex lens and a laser, the container has a cavity for containing liquid, the cavity comprises a circular flow channel and a straight flow channel, the straight flow channel is located in the tangent direction of the circular flow channel and penetrates through it, the metal substrate is blocked at the inlet end of the straight flow channel, and the light emitted by the laser is focused by the convex lens and irradiated on the metal substrate to drive the liquid to move.

[0010] In the above scheme, the cavity composed of the straight flow channel and the circular flow channel tangent to each other is used to contain the liquid driven by the laser, and the flow state of the liquid is converted to rotation. The metal substrate is placed at the inlet end of the straight flow channel (i.e. the end of the straight flow channel not tangent to the circular flow channel), which is used to accept the energy of the laser to generate the power of the liquid flow in the cavity. The above cavity converts the flow path of the liquid by the cooperation of the straight flow channel and the circular flow channel, which can realize long-range and stable liquid circulation driven by laser, and well retains the long-range and stability of linear motion.

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

[0012] As a preferred scheme of the present application, the liquid comprises deionized water or a gold nanoparticle solution.

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

[0014] As a preferred scheme of the present application, 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 value of the outer boundary of the annular flow channel.

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

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

[0017] As a preferred scheme of the present application, a notch is provided on the side wall of the container 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 scheme of the present application, the metal substrate is perpendicular to the central axis direction of the straight flow channel, and the light emitted by the laser is focused and irradiated at the position where the central axis of the straight flow channel intersects with the metal substrate.

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

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

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

[0022] 2. The control source of the present application is single, and the control precision is high. Except for the laser as the control source, no other physical field needs to be added, the requirement for the experimental environment construction is low, and the fewer control sources also make the results not affected by other redundant conditions, but strictly related to the laser power, and the controllability is strong.

[0023] 3、The present application is non-contact, does not need any external rotating shaft, wire connection, laser source can be remote control, not directly contact with the device, higher flexibility;

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

[0025] In order to more clearly illustrate the technical scheme of the exemplary embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows, and it should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor. In the drawings:

[0026] Figure 1 It is a schematic view of the device for laser-driven liquid rotation in the present application in the overhead direction;

[0027] Figure 2 It is a schematic view of the container A-A in the present application; Figure 1

[0028] Figure 3 It is a schematic view of the container in the present application in the solid state; Figure 1

[0029] Figure 4 It is the experimental result of laser-driven liquid straight jet in the present application;

[0030] Figure 5 It is a schematic view of the laser-driven liquid rotation state in the present application;

[0031] Figure 6 It is the flow field condition simulated in the COMSOL finite element simulation software in the present application;

[0032] Figure 7 It is the curve of the driving laser power and the liquid rotation flow rate relationship in the present application.

[0033] Markings in the drawings and corresponding names of parts:

[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 purpose, technical scheme and advantages of the present application more clear and obvious, the present application will be further described in detail below combined with embodiments and drawings, the exemplary embodiments of the present application and the description thereof are only used to explain the present application, and should not be regarded as a limitation on the present application.​​

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art 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" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions 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] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, 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 this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0040] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this 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 orientations or positional relationships indicated by the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are merely for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot 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 explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium; can be the communication or interaction relationship between two elements. For those skilled 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 The device for driving liquid to rotate by laser provided in the embodiments 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 containing liquid. The cavity includes an annular flow channel 11 and a straight flow channel 12. The straight flow channel 12 is located in the tangent direction of the annular flow channel 11 and penetrates through the annular flow channel 11. 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 then irradiated on the metal substrate 2 to drive the liquid to move.

[0045] In the embodiments, the cavity composed of the straight flow channel 12 and the annular flow channel 11 tangent to each other is used to contain the liquid driven by laser and convert the flow state of the liquid into rotation. The metal substrate 2 is placed at the inlet end of the straight flow channel 12 (i.e. the end of the straight flow channel 12 which is not tangent to the annular flow channel 11) to receive the energy of laser and generate the power of the liquid flow in the cavity. The above-mentioned cavity converts the flow path of the liquid by the cooperation of the straight flow channel 12 and the annular flow channel 11, which can realize the long-range and stable liquid circulation driven by laser, and well retains the long-range and stability of linear motion.

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

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

[0048] According to some embodiments of the present application, the liquid can be deionized water or a gold nanoparticle solution. In order to better achieve the flow phenomenon, both of the above-mentioned liquids can be used, so as to reduce the influencing factors. It should be noted that the container 1 for containing the liquid should not be made of a material that is particularly hydrophilic or hydrophobic. Exemplary containers 1 can be made of resin or glass, 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 development of the laser path, so as to 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 that of the annular flow channel 11, and the length L of the straight flow channel 12 is slightly smaller than the radius value 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 straight in the straight flow channel 12, and part of the liquid enters the annular flow channel 11 and forms 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, and the energy converted by the metal substrate 2 cannot drive part of the liquid to enter 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 30-40mm. By designing the cross section of the annular flow channel 11 to be rectangular, this regular cross-sectional shape facilitates the manufacture of the annular flow channel 11 on the container 1.

[0052] According to some embodiments of the present application, the container 1 is disc-shaped, and part of the top surface of the container 1 is recessed downward to form the cavity. After the above scheme is used, the top of the cavity coincides with the top surface of the container 1, i.e. the top of the cavity is in an open state, so that the straight flow channel 12 and the annular flow channel 11 can be directly machined by turning and milling processes.

[0053] According to some embodiments of the present application, the container 1 is provided with a notch on the side wall opposite to the inlet end of the straight flow channel 12, and the metal substrate 2 is arranged 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, the metal substrate 2 is conveniently installed and fixed 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 direction of the straight flow channel 12, and the light emitted by the laser 3 is irradiated at the position where the central axis of the straight flow channel 12 intersects with the metal substrate 2 after being focused. By adopting the above technical solution, the effect of laser driving 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, the present embodiment uses a 532 nm semiconductor laser as a control source, and other green light lasers with a wavelength near 527 nm can also be used. The power is controllable between 0 and 500 milliwatts, the liquid is deionized water, and the metal substrate 2 for converting laser energy is a 2 mm transparent glass substrate plated with a 300 nm gold layer for related experiments.

[0057] Figure 4 The laser-driven liquid straight flow situation achieved when the laser is incident on the metal substrate 2 in a common rectangular container 1 is shown. Under the function of fluorescent particle coloration, a long-range and stable straight jet can be seen, and when the laser power is 200 milliwatts, the jet speed is about 4 cm / s. This also proves that the metal substrate 2 can achieve a driving function.

[0058] Figure 5 The laser-driven liquid rotation state in the present embodiment is shown. The light emitted by the 532 nm 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 straight in the straight flow channel 12. When the flow state reaches the annular flow channel 11, the liquid is subjected to a larger 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 flow channel 12. The small vortex formed will also become the driving force for the liquid in the entire cavity to flow naturally, driving the large circulation in the annular flow channel 11.

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

[0060] Figure 7 The driving laser power and liquid rotational flow rate relationship curve used in the embodiment is shown, and it can be found that the laser power is substantially positively correlated with the liquid rotational flow rate, and the relationship diagram can be used for accurate control of the flow rate.

[0061] The above specific embodiments further illustrate the purposes, technical solutions and beneficial effects of the present application, and it should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application, and any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

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 holding 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 it, 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 then irradiated onto the metal substrate to drive the movement of the liquid, and the metal substrate comprises a quartz substrate injected with gold ions or a glass substrate plated with a 200-500nm gold layer.

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

3. The laser-driven liquid rotation device according to claim 2, characterized in that: Fluorescent particles are added to the liquid to increase the color of the laser path.

4. 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 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.

5. The laser-driven liquid rotation device according to claim 4, characterized in that: The cross section of the annular flow channel is rectangular, and the width in the radial direction is 30-40 mm.

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

7. The laser-driven liquid rotation device according to claim 6, 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 seal the inlet end of the straight flow channel.

8. 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.

9. 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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