CN111551294B - Flexible pressure sensor based on liquid metal photocuring printing technology - Google Patents
Flexible pressure sensor based on liquid metal photocuring printing technology Download PDFInfo
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- CN111551294B CN111551294B CN202010436003.5A CN202010436003A CN111551294B CN 111551294 B CN111551294 B CN 111551294B CN 202010436003 A CN202010436003 A CN 202010436003A CN 111551294 B CN111551294 B CN 111551294B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
- G01L1/205—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using distributed sensing elements
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
- B29C64/10—Processes of additive manufacturing
- B29C64/106—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
- B29C64/124—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material using layers of liquid which are selectively solidified
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y10/00—Processes of additive manufacturing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y70/00—Materials specially adapted for additive manufacturing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y80/00—Products made by additive manufacturing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/18—Measuring force or stress, in general using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
Abstract
The invention discloses a flexible pressure sensor based on a liquid metal photocuring printing technology. The flexible sensor is prepared by photocuring printing; the flexible sensor is internally provided with a micro-channel structure; the micro-channel structure comprises two channels which are centrosymmetric; each channel mainly comprises an arc-shaped channel I, an arc-shaped channel II and a bent channel, wherein one end of the arc-shaped channel I of the two channels is respectively connected with two inlets in the micro-channel structure; the curved channel is in a triangular shape and protrudes towards the upper end; the lower part of the flexible sensor is of a columnar structure, and the upper part of the flexible sensor is of a circular vault structure; inlets on two sides of the flexible sensor are respectively connected with the lead; and packaging the flexible sensor connected with the lead by adopting PDMS to obtain a packaging layer for packaging the flexible sensor. The invention designs a three-dimensional micro-channel structure in the sensor by utilizing the characteristic that the resistance of the liquid metal can change under the action of external force, so that the sensor has the function of measuring the contact force.
Description
Technical Field
The invention relates to a pressure sensor, in particular to a flexible pressure sensor based on a liquid metal photocuring printing technology.
Background
Flexible sensors are rapidly developing in the fields of medical services, robots, wearable electronics, and the like due to their unique flexibility and adaptability.
The traditional flexible pressure sensor is generally manufactured by PDMS, and has the problems of single micro-channel structure, poor micro-channel stereoscopy, complex manufacturing process, single function and the like, and the flexible sensor manufactured by PDMS at present has the defects of poor sensitivity, large return error, nonlinear input and output relation and the like, so that the flexible sensor is not suitable for complex application scenes, and therefore, the flexible pressure sensor is necessary to be manufactured by developing new materials and new molding technology.
With the release of the national 3D printing development plan "national additive manufacturing industry development push plan" and the emergence of the planning outline of "2025 for chinese manufacturing", the 3D printing technology is gradually maturing, and at the same time, the strong productivity thereof is exhibited in the field of industrial manufacturing.
The liquid metal material has high surface tension, high conductivity, low toxicity and low viscosity, so the liquid metal material is very wide in the application fields of wearable robots, flexible sensors and retractable electronic products, and in the flexible pressure sensors, the change of pressure can be mapped through the change of the resistance of the liquid metal.
At present, with the continuous development of intelligent manufacturing and additive manufacturing technologies, the application fields of flexible pressure sensors are wider and wider, such as the fields of medical services, soft robots, wearable electronic devices and the like. Therefore, development and improvement of flexible sensors are inevitable trends.
Disclosure of Invention
In order to solve the problems in the background art, the invention provides a flexible pressure sensor based on a liquid metal photocuring printing technology, which utilizes the characteristic that the resistance of liquid metal changes under the action of external force, and designs a three-dimensional micro-channel structure in the sensor, so that the sensor has the function of measuring contact force. The manufacturing of the sensor can be realized by utilizing the photocuring 3D printing technology, and the manufacturing process is simplified.
The technical scheme adopted by the invention is as follows:
flexible pressure sensor based on liquid metal photocuring printing technology
The flexible sensor is prepared by photocuring printing;
the flexible sensor is internally provided with a micro-channel structure, and two symmetrical small holes are arranged at two sides of the flexible sensor and are used as two inlets of the micro-channel structure;
the micro-channel structure comprises two channels which are centrosymmetric; each channel mainly comprises an arc-shaped channel I, an arc-shaped channel II and a bent channel, the arc-shaped channel I and the arc-shaped channel II are concentric arcs, and one end of the arc-shaped channel I of the two channels is connected with two inlets in the micro-channel structure respectively; one end of the arc-shaped channel I is connected with one inlet in the micro-channel structure, the other end of the arc-shaped channel I is connected with one end of the arc-shaped channel II after being bent towards the center of the micro-channel structure, the other end of the arc-shaped channel II is connected with one end of the bent channel after being bent towards the center of the micro-channel structure, and the other end of the bent channel is connected with the other inlet in the micro-channel structure; the bent channel is lifted upwards and then gradually descended, the lifting length is equal to the descending length, the bent channel is protruded towards the upper end in a triangular shape, and a three-dimensional micro-channel structure is formed;
the lower part of the flexible sensor is a columnar structure, the upper part of the columnar structure is a circular arch crown structure, the arch crown structure is used as a stress deformation surface, and the central bending degree corresponds to an upward convex bending channel in the micro-channel structure;
inlets on two sides of the flexible sensor are respectively connected with the lead; and packaging the flexible sensor connected with the lead by adopting PDMS to obtain a packaging layer for packaging the flexible sensor.
Liquid metal is injected into the micro-channel structure in the flexible sensor to form a sensitive element of the pressure sensor, the liquid metal is respectively in full contact with the leads on the two sides to prevent reaction failure caused by poor contact, and the leads are connected with external measuring equipment;
when the flexible sensor is stressed, the shape of the micro-channel structure changes, the micro-channel structure is mapped into the change of the resistance of the micro-channel structure through liquid metal, then an electric signal is output through a lead, and external measuring equipment converts the information of the electric signal into data of the pressure stressed on the flexible sensor.
The liquid metal is gallium (Ga), gallium (Ga) -indium (In) alloy, gallium (Ga) -indium (In) -tin (Sn) alloy and one of transition metal and solid nonmetal elements, or is doped by two or more than two metals of gallium, gallium-indium alloy or gallium-indium-tin alloy.
The process of encapsulating with PDMS is: after liquid metal is injected into the micro-channel structure of the flexible sensor, the leads are respectively inserted into the inlets at two sides of the micro-channel structure; and then placing the flexible sensor into a groove of a packaging mold, pouring PDMS into the packaging mold until the PDMS just submerges the top of the flexible sensor, placing the whole on a heating table, heating at a constant temperature for 30min until the whole is cured and molded, and taking out the whole to obtain the required flexible pressure sensor based on the liquid metal photocuring printing technology.
The middle of the packaging mold is provided with a groove, the groove is composed of a rectangular groove and a circular groove, the circular groove is located in the center of the groove and used for placing the flexible sensor, two sides of the circular groove respectively extend towards two sides to form two rectangular grooves, and wires on two sides of the flexible sensor extend along the rectangular grooves.
The channel section of the micro-channel structure in the flexible sensor is rectangular, the section size of the joint of the arc-shaped channel I and the arc-shaped channel II is larger than that of the two arc-shaped channels, the turning positions of the convex structures on the two sides in the bent channel are set to be cylindrical structures for transition, when the shape of the micro-channel changes, the phenomenon that liquid metal is blocked or the micro-channel rebounds and delays is avoided, and the stability, the sensitivity, the durability and the flexibility of liquid flowing of structural manufacturing are considered.
The distance between two adjacent micro-channels in the micro-channel structure is not less than 1.8 times of the width of the cross section of the micro-channel due to the insufficient strength and toughness of the material; the height of the section of the micro flow channel is 70-80% of the thickness of the flexible sensor; the volume of the micro-channel in the flexible sensor is 20-30% of the volume of the whole flexible sensor.
The two adjacent flow passages comprise an arc-shaped passage I, an arc-shaped passage II and a bent passage, and the bent passages of the two passages
The printing material for photocuring printing by the flexible sensor adopts the following configuration method:
the first step is as follows: the organic silicon rubber 8411 and the organic silicon rubber 110 are proportioned according to the mass ratio of 2:3 to be used as a base material of a printing material;
the second step is that: adding TPO-L into the base material in the first step, wherein the mass of the TPO-L is 20% of that of the base material, and the TPO-L is used as a photoinitiator for promoting photocuring;
the third step: adding DMF (dimethyl formamide) into the material obtained in the second step, wherein the mass of the DMF is 2% of that of the material obtained in the second step, and the DMF is used as an organic solvent with good performance to promote the dissolution and mixing of the material;
fourthly, adding solid Sudan red into the material obtained in the third step, wherein the mass of the Sudan red is 0.1% of that of the material obtained in the third step, and the Sudan red is used as a light absorber for preventing a flow channel from being blocked due to over-solidification in the printing process;
and fifthly, placing the material obtained in the fourth step on a constant-temperature magnetic stirring table at 50 ℃ to stir and mix for about 30min until no suspended solid particles appear, and obtaining the required printing material.
Second, application of the flexible pressure sensor
The flexible pressure sensor is applied to the fields of soft robots, intelligent wearable equipment and the like, and is wide in application scene.
The invention has the beneficial effects that:
(1) the invention replaces the original method for manufacturing the micro-channel by using the photocuring 3D printing technology, reduces the cost, expands the model design and improves the controllability of the manufacturing process of the flexible pressure sensor. By using the new material, the defects of high energy consumption, complex manufacturing process, small product deformation degree and the like in the existing flexible sensor manufacturing process are overcome, the rapid, green and low-cost manufacturing is realized, and the development of the 3D printing micro-channel technology is promoted
(2) The whole sensor substrate is molded layer by layer through photocuring printing, the positive stress is linearly mapped into resistance change based on a skillfully designed three-dimensional micro-channel structure, and the positive stress applied to the sensor is measured by measuring the resistance change caused by the deformation of liquid metal. The micro-channel structure of the invention fully utilizes the area of the sensor, improves the filling amount of liquid metal and ensures that the sensor has good sensitivity. The liquid metal material is adopted in the flow channel, and the surface tension and the electric conductivity are high.
(3) The flexible sensor has better flexibility and stability, can be attached to the surfaces of soft robots and wearable electronic equipment, and the fields of soft robots, intelligent wearable equipment and the like, can map the change of pressure through the change of liquid metal resistance, and can be widely applied to the aspects of data acquisition, medical service and the like.
Drawings
Fig. 1 is a schematic structural diagram of the flexible sensor (1), (a) is a perspective view of the flexible sensor (1), (b) is a top view of the flexible sensor (1), (c) is a side view of the flexible sensor (1), and (d) is a sectional view of the flexible sensor (1).
Fig. 2 is a schematic view of a 3D print sensor of the present invention.
Fig. 3 is a schematic diagram of the manufacturing process of the package of the present invention, wherein (a) is a structural diagram of the completed package of the present invention, and (b) is a cross-sectional diagram of the completed package of the present invention.
Fig. 4 is a schematic view of a pressure glove based on a flexible sensor (1).
In the figure: 1. flexible sensor, 2, arc passageway I, 3, arc passageway II, 4, crooked passageway, 5, objective table, 6, container, 7, reflector, 8, printer chip, 9, encapsulation layer, 10, slide glass, 11, wire, 12, packaging mould
Detailed Description
The invention is further described below with reference to the figures and examples.
As shown in fig. 1, a micro-channel structure is arranged inside a flexible sensor 1, and the micro-channel structure comprises two channels which are centrosymmetric; each channel mainly comprises an arc channel I2, an arc channel II 3 and a bent channel 4, the arc channel I2 and the arc channel II 3 are concentric arcs, and one end of the arc channel I2 of the two channels is connected with two inlets in the micro-channel structure respectively; one of them entry links to each other in arc passageway I2 one end and the microchannel structure, and arc passageway I2 other end links to each other with the one end of arc passageway II 3 after towards the microchannel structure center bending, and the other end of arc II links to each other with 4 one ends of crooked passageway after towards the microchannel structure center bending, and another entry linkage in 4 other ends of crooked passageway and the microchannel structure. The micro-channel structure of the invention fully utilizes the area of the sensor to arrange liquid metal as much as possible, thereby increasing the sensitivity.
As shown in fig. 1(a), the outer ring of the micro flow channel structure inside the flexible sensor 1 is similar to a disc type structure, and the flow channel at the central part is protruded upwards to form a three-dimensional micro flow channel structure. As shown in fig. 1(b), the cross-sectional view is taken along the edge of the microchannel, the outer ring is a half-circle ring, and the two ends of the ring are staggered and extend to the center respectively until the three-dimensional microchannel structure is connected to the center. As shown in fig. 1(c), a micro flow channel structure is arranged inside the flexible sensor 1, and two symmetrical small holes are formed at two sides of the flexible sensor 1 as two inlets of the micro flow channel structure; the two inlets serve as channels for connecting the liquid metal inside the microchannel with external measuring equipment. Liquid metal enters and exits from these two inlets. As shown in fig. 1(d), the curved passage 4 is first raised upward and then gradually lowered, and the raised length is equal to the lowered length. And finally, the micro-channel at the central part is connected with the arc-shaped channel I2 of the other channel to form a circulating structure. The distance between two adjacent micro-channels is not less than 1.25 mm.
In the implementation, considering the stability of the structure and the precision of the manufacturing, and the continuity of the deformation process, we designed the micro flow channel with a rectangular cross section, and the cross section size of the micro flow channel is 0.9mm by 0.7 mm. In the aspect of the arrangement of the overall size of the sensor, the accuracy of stress sensing and the actual application scene of the sensor are comprehensively considered, the outer contour of the overall sensor is designed to be circular, and the design size of the overall sensor is designed to be phi 12 mm. The distance between each micro flow channel is not less than 1.25mm, which is limited by the insufficient strength and toughness of the material.
Fig. 2 shows a manufacturing process of the photo-curing printing flexible sensor 1. In the printing process, an inverted photocuring 3D printer is used, and 8 in the figure represents a chip of the printer. In the specific printing process, firstly, the printing parameters including the exposure time of each layer and the number of slices are set, and the software slices the model according to the number of slices parameters. The ultraviolet light is then controlled to impinge on the chip, which will display the pattern of each slice. As shown is a picture of a slice of the flexible sensor 1 that appears after the pattern on the chip has been magnified. The ultraviolet light then reflects the pattern through a mirror 7 into a container 6 filled with printing material, in which case the stage 5 is in close contact with the container 6, here separated for the purpose of illustrating the structure. The printed flexible sensor 1 is positioned between the stage 5 and the container 6, and the layer of the currently printed flexible sensor 1 is directly attached to the printed flexible sensor 1. Finally, after all the cut sheet layers are printed, the flexible sensor 1 is obtained from the object stage 5. Supplementary explanation prints the layer thickness to be each time carry on ultraviolet light solidify the distance that the printing platform moves up, namely the thickness printed in a layer each time; the exposure time is the time for each layer of slices to be exposed by ultraviolet rays after the printing table is moved and stands; the exposure of the bottom layer is the exposure time of the first layers; setting a larger number of bottom layers helps to stabilize the mold, but it will destroy the original shape, so it is more appropriate to take 4 layers. And importing the designed stl file of the sensor structure into a printer program, clicking the section to run a corresponding path planning algorithm, and then carrying out photocuring printing.
As shown in fig. 3, the printed flexible sensor 1 is connected to a lead 11, and then placed in a packaging mold 12, and then PDMS serving as a packaging material is poured into the packaging mold 12, and is cured by heating the PDMS to achieve adhesive sealing.
As shown in fig. 3(a), the flexible sensor 1 comprises an encapsulation layer 9 and a flexible sensor 1 with a micro flow channel structure, which are sequentially stacked from top to bottom, wherein the flexible sensor 1 is manufactured by a photocuring 3D printing technology, and is bonded and sealed with the encapsulation layer 9 by PDMS. The three-dimensional structure of the mold is shown. The mold may be manufactured by 3D printing, casting, or the like. The middle of the die is a hollow circle, the flexible sensor 1 can be placed in the die, then a rectangular structure is overlapped with the center of the hollow circle, the length of the rectangle is 48mm, the width of the rectangle is 25mm, and a 0.3mm thick lead 11 can be placed in the rectangle.
Specifically, after the flexible sensor 1 in fig. 1(a) is printed according to the structures shown in fig. 1(b), fig. 1(c) and fig. 1(d), liquid metal is firstly introduced, the lead 11 is inserted into the small holes at the two ends, the flexible sensor 1 is placed into the mold shown in 5 in fig. 3, the packaging mold 12 with the flexible sensor 1 placed therein is placed on the glass slide 103 in fig. 2, sufficient PDMS is poured into the packaging mold 12 to form the packaging layer 95 in fig. 3, and then the packaging layer is placed on a heating table and taken out after the heating and curing are completed. The resistance change of the flexible sensor 1 can be measured in real time by connecting the lead 11 of fig. 3 4 with a precision resistance meter. The change in resistance is converted to pressure data as a function of the fit.
As shown in fig. 4, each packaged flexible sensor 1 is placed on a rubber glove, two flexible sensors 1 are placed on the thumb and the little finger according to the direction of the thumb, three flexible sensors 1 are placed on the remaining three fingers, and each flexible sensor 1 is connected through a lead 11, so that the array of the flexible sensors 1 on the rubber glove is realized.
The flexible sensor 1 is implemented by using silicone rubbers 8411 and 110 as a substrate, TPO-L as a light curing agent, DMF as an organic solvent, Sudan red as a light absorber, and PDMS as a material of the encapsulation layer 9.
The liquid metal comprises gallium (Ga), gallium (Ga) -indium (In) alloy, gallium (Ga) -indium (In) -tin (Sn) alloy, and one or more of transition metal and solid nonmetal elements doped with gallium, gallium-indium alloy and gallium-indium-tin alloy.
The working principle of the invention is as follows:
the flexible sensor 1 of the present invention can be attached to an electronic device when attached to the surface of the electronic device. The flexible sensor 1 is internally designed with a micro-channel structure and is injected with liquid metal. When the sensor contacts with an object and deforms, the size of the cross section of the flow channel changes, so that the resistance of the liquid metal changes. And calculating the actually measured resistance value, and converting the electric signal into the measurement of the contact force.
The liquid metal is injected into the sensor sensing element formed by the micro-channel structure, and then the change of the self-resistance is output through the external lead 11 as follows:
when the bulge structure of the flexible sensor 1 is subjected to downward pressure, the bulge structure can extrude the liquid metal in the structure flow channel, the size of the cross section of the liquid metal is changed, the overall resistance of the liquid metal in all the communicated micro-flow channels is further changed, and the downward pressure data detected by the electric signal is further output.
The manufacturing method of the invention comprises the following steps:
firstly, configuring the material for photocuring printing
In the first step, liquid silicone rubbers 8411 and 110 are used, and the mass ratio of the two is 2:3, so as to be used as a substrate of a printing material.
And secondly, on the basis of obtaining the base material, adding TPO-L in an amount of 20% of the mass of the base material, wherein the TPO-L is used as a photoinitiator to promote the photocuring process of the material.
And thirdly, on the basis of obtaining the material, adding DMF (dimethyl formamide) in an amount of 2% of the mass of the material, wherein the DMF is used as an organic solvent with good performance and promotes the dissolution and mixing of the material.
Fourthly, on the basis of obtaining the material, Sudan red is added in an amount of 0.1 percent of the mass of the material, and the Sudan red is used as a light absorber to prevent the blockage of a flow channel caused by over-solidification in the printing process.
And fifthly, on the basis of obtaining the material, stirring and mixing the material on a constant-temperature magnetic stirring table at 50 ℃ for about 30min until no suspended solid particles appear, and obtaining the 3D printed material.
Two, 3D printing
The printing adopts an inverted photocuring 3D printer. Firstly, preparing a container 6, coating a layer of PDMS on the surface of the container 6 and curing, then pouring the material into the container 6, and fixing the container 6 on the corresponding position of the printer. Before the initial printing, the printer is set with parameters such as the exposure time of a single layer, the thickness of a printing layer, and the like.
The photocuring 3D printing is realized by layered printing, wherein the thickness of the printing layer is the distance of the printing platform moving upwards when the ultraviolet photocuring is carried out each time, namely the thickness of one layer of printing each time; the exposure time is the time for each layer of slices to be exposed by ultraviolet rays after the printing platform moves and stands; the exposure of the bottom layer is the exposure time of the first layers; setting a larger number of bottom layers helps to stabilize the mold, but it will destroy the original shape, so it is more appropriate to take 4 layers.
And importing the stl file of the designed flexible sensor 1 structure into a printer program, clicking the section to run a corresponding path planning algorithm, and then carrying out photocuring printing.
Third, pour into the liquid metal and capsulate
After printing is finished, the printed flexible sensor 1 is taken out of the printing platform, the flexible sensor 1 is firstly placed into an ultrasonic oscillator filled with ethanol solution, redundant uncured printing materials in the micro-channel are removed, and then liquid metal is filled into the flexible sensor 1 by using an injector. And selecting a gallium indium tin alloy (the mass ratio of Ga: In: Sn is 62:22:16) as a liquid metal material, injecting the liquid metal into the manufactured flexible sensor 1, and respectively inserting the leads 11 into the micro-channel access holes to ensure that the leads 11 are fully contacted with the liquid metal. The liquid metal is filled and then packaged, PDMS is adopted for packaging in the method, the two ends of the sensor foundation firmware are connected with the wires 11 and then placed in a packaging model, PDMS is poured to just submerge the top of the sensor, the model and the packaging material are placed on a heating table for constant temperature heating for 30min until molding is finished, and the model and the packaging material are taken out. The final flexible sensor 1 is removed.
The flexible sensor 1 designed by the invention directly completes integrated molding by using flexible materials, has better flexibility and stability, and effectively solves the problem of inevitable installation errors in the packaging process of the PDMS mold compared with the flexible sensor 1 which is mostly manufactured by adopting the PDMS mold at present. In addition, most of the flexible sensors 1 on the market adopt simple planar structures, and the invention innovatively designs a three-dimensional micro-channel structure based on the superiority of photocuring 3D printing, so that the sensitivity of the flexible sensors 1 to stress is increased, and the discrimination of forces in different directions is improved.
The foregoing detailed description is intended to illustrate and not limit the invention, which is intended to be within the spirit and scope of the appended claims, and any changes and modifications that fall within the true spirit and scope of the invention are intended to be covered by the following claims.
Claims (9)
1. The utility model provides a flexible pressure sensor based on liquid metal photocuring printing technique which characterized in that: the flexible sensor comprises a flexible sensor (1), a lead (11) and a packaging layer (9), wherein the flexible sensor (1) is prepared by photocuring printing;
the flexible sensor (1) is internally provided with a micro-channel structure, and two symmetrical small holes are arranged at two sides of the flexible sensor (1) and are used as two inlets of the micro-channel structure;
the micro-channel structure comprises two channels which are centrosymmetric; each channel mainly comprises an arc channel I (2), an arc channel II (3) and a bent channel (4), the arc channel I (2) and the arc channel II (3) are concentric arcs, and one end of the arc channel I (2) of each channel is connected with two inlets in the micro-channel structure respectively; one end of the arc-shaped channel I (2) is connected with one inlet in the micro-channel structure, the other end of the arc-shaped channel I (2) is connected with one end of the arc-shaped channel II (3) after being bent towards the center, the other end of the arc-shaped channel II (3) is connected with one end of the bent channel (4) after being bent towards the center, and the other end of the bent channel (4) is connected with the other inlet in the micro-channel structure; the bent channel (4) is lifted upwards and then gradually lowered, the lifting length is equal to the lowering length, and the bent channel is protruded towards the upper end in a triangular shape;
the lower part of the flexible sensor (1) is a columnar structure, the upper part of the columnar structure is a circular arch structure, the arch structure is used as a stress deformation surface, and the central bending degree corresponds to a bending channel (4) which is convex upwards in the micro-channel structure;
inlets on two sides of the flexible sensor (1) are respectively connected with the lead (11); and packaging the flexible sensor (1) connected with the lead (11) by adopting PDMS to obtain a packaging layer (9) for packaging the flexible sensor (1).
2. The flexible pressure sensor based on liquid metal photocuring printing technology of claim 1, wherein: liquid metal is injected into the micro-channel structure in the flexible sensor (1) to form a sensitive element of the pressure sensor, the liquid metal is respectively and fully contacted with the leads (11) at two sides, and the leads (11) are connected with external measuring equipment;
when the flexible sensor (1) is stressed, the shape of the micro-channel structure changes, the micro-channel structure is mapped to the change of the resistance of the micro-channel structure through liquid metal, then an electric signal is output through a lead (11), and external measuring equipment converts the information of the electric signal into data of the pressure stressed on the flexible sensor (1).
3. The flexible pressure sensor based on liquid metal photocuring printing technology as claimed in claim 2, wherein: the liquid metal is gallium (Ga), gallium (Ga) -indium (In) alloy, gallium (Ga) -indium (In) -tin (Sn) alloy and one of transition metal and solid nonmetal elements, or is doped by two or more than two metals of gallium, gallium-indium alloy or gallium-indium-tin alloy.
4. The flexible pressure sensor based on liquid metal photocuring printing technology of claim 3, wherein: the process of encapsulating with PDMS is: after liquid metal is injected into a micro-channel structure of the flexible sensor (1), leads (11) are respectively inserted into inlets at two sides of the micro-channel structure; and then placing the flexible sensor (1) into a groove of a packaging mold (12), pouring PDMS into the packaging mold (12) until the PDMS just submerges the top of the flexible sensor (1), placing the whole on a heating table, heating at a constant temperature for 30min, and taking out after curing and forming to obtain the required flexible pressure sensor based on the liquid metal photocuring printing technology.
5. The flexible pressure sensor based on liquid metal photocuring printing technology of claim 4, wherein: the middle of the packaging mold (12) is provided with a groove, the groove is composed of a rectangular groove and a circular groove, the circular groove is located in the center of the groove and used for placing the flexible sensor (1), two sides of the circular groove extend towards two sides respectively to form two rectangular grooves, and wires (11) on two sides of the flexible sensor (1) extend to the outside along the rectangular grooves.
6. The flexible pressure sensor based on liquid metal photocuring printing technology of claim 1, wherein: the section of the channel of the micro-channel structure in the flexible sensor (1) is rectangular, the section size of the joint of the arc-shaped channel I (2) and the arc-shaped channel II (3) is larger than that of the two arc-shaped channels, and when the shape of the micro-channel changes, liquid metal is prevented from being blocked or the micro-channel is prevented from rebounding and delaying.
7. The flexible pressure sensor based on liquid metal photocuring printing technology of claim 1, wherein: the distance between two adjacent micro channels in the micro channel structure is not less than 1.8 times of the width of the cross section of the micro channel; the height of the section of the micro-channel is 70-80% of the thickness of the flexible sensor; the volume of a micro flow channel in the flexible sensor is 20-30% of the volume of the whole flexible sensor (1).
8. The flexible pressure sensor based on liquid metal photocuring printing technology of claim 1, wherein: the printing material for the flexible sensor (1) to perform photocuring printing adopts the following configuration method:
the first step is as follows: the organic silicon rubber 8411 and the organic silicon rubber 110 are proportioned according to the mass ratio of 2:3 to be used as a base material of a printing material;
the second step is that: adding TPO-L into the base material in the first step, wherein the mass of the TPO-L is 20% of that of the base material, and the TPO-L is used as a photoinitiator for promoting photocuring;
the third step: adding DMF (dimethyl formamide) into the material obtained in the second step, wherein the mass of the DMF is 2% of that of the material obtained in the second step, and the DMF is used as an organic solvent to promote the dissolution and mixing of the material;
fourthly, adding solid Sudan red into the material obtained in the third step, wherein the mass of the Sudan red is 0.1% of that of the material obtained in the third step, and the Sudan red is used as a light absorber for preventing micro-channels from being blocked due to over-curing in the printing process;
and fifthly, placing the material obtained in the fourth step on a constant-temperature magnetic stirring table at 50 ℃ for stirring and mixing for 30min until no suspended solid particles appear, and obtaining the required printing material.
9. Use of a flexible pressure sensor according to any of claims 1 to 8, wherein: the flexible pressure sensor is applied to a soft robot and intelligent wearable equipment.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112326076A (en) * | 2020-11-04 | 2021-02-05 | 重庆大学 | Pressure sensor and installation mechanism thereof |
| CN112880547B (en) * | 2021-01-14 | 2022-05-20 | 华中科技大学 | Liquid metal-based touch sensor, array and preparation method thereof |
| CN114234792B (en) * | 2021-12-23 | 2023-10-03 | 太原理工大学 | Resistance type flexible pressure sensor capable of measuring bending strain and preparation method thereof |
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| CN115014590B (en) * | 2022-06-16 | 2023-10-20 | 东华大学 | Piezoelectric sensor and preparation method thereof |
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Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012033837A3 (en) * | 2010-09-08 | 2012-06-07 | Micropen Technologies Corporation | Pressure sensing or force generating device |
| CN102589759A (en) * | 2012-02-20 | 2012-07-18 | 浙江大学 | Bionic flexible touch sense sensing array based on piezoresistive type and capacitance type combination |
| CN106793536A (en) * | 2016-11-17 | 2017-05-31 | 华中科技大学 | A kind of flexible electronic preparation method based on microflow control technique |
| JP6183599B2 (en) * | 2013-08-20 | 2017-08-23 | セイコーエプソン株式会社 | Piezoelectric element manufacturing method, liquid jet head manufacturing method, and ultrasonic transducer manufacturing method |
| CN107414080A (en) * | 2016-05-23 | 2017-12-01 | 中国科学院理化技术研究所 | Liquid metal 3D printing ejecting device and the 3D printer provided with the device |
| CN108007617A (en) * | 2017-12-05 | 2018-05-08 | 浙江大学 | Pressure resistance type flexible touch sensation sensor and its manufacture method with micro- frustum of a cone substrate |
| CN109323784A (en) * | 2018-09-21 | 2019-02-12 | 浙江大学 | A kind of pressure resistance type flexible touch sensation sensor with the double-deck snap-type micro-boss |
| CN110361118A (en) * | 2019-05-08 | 2019-10-22 | 中国科学院宁波材料技术与工程研究所 | A kind of flexible sensor, preparation method and application method |
| CN110375895A (en) * | 2019-07-18 | 2019-10-25 | 浙江大学 | Multi-functional Grazing condition finger print touch sensor |
| CN110763378A (en) * | 2019-11-01 | 2020-02-07 | 浙江大学 | Wearable flexible touch force sensor |
| CN110987246A (en) * | 2019-12-17 | 2020-04-10 | 浙江清华柔性电子技术研究院 | Flexible sensor and preparation and use methods thereof |
-
2020
- 2020-05-21 CN CN202010436003.5A patent/CN111551294B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012033837A3 (en) * | 2010-09-08 | 2012-06-07 | Micropen Technologies Corporation | Pressure sensing or force generating device |
| CN102589759A (en) * | 2012-02-20 | 2012-07-18 | 浙江大学 | Bionic flexible touch sense sensing array based on piezoresistive type and capacitance type combination |
| JP6183599B2 (en) * | 2013-08-20 | 2017-08-23 | セイコーエプソン株式会社 | Piezoelectric element manufacturing method, liquid jet head manufacturing method, and ultrasonic transducer manufacturing method |
| CN107414080A (en) * | 2016-05-23 | 2017-12-01 | 中国科学院理化技术研究所 | Liquid metal 3D printing ejecting device and the 3D printer provided with the device |
| CN106793536A (en) * | 2016-11-17 | 2017-05-31 | 华中科技大学 | A kind of flexible electronic preparation method based on microflow control technique |
| CN108007617A (en) * | 2017-12-05 | 2018-05-08 | 浙江大学 | Pressure resistance type flexible touch sensation sensor and its manufacture method with micro- frustum of a cone substrate |
| CN109323784A (en) * | 2018-09-21 | 2019-02-12 | 浙江大学 | A kind of pressure resistance type flexible touch sensation sensor with the double-deck snap-type micro-boss |
| CN110361118A (en) * | 2019-05-08 | 2019-10-22 | 中国科学院宁波材料技术与工程研究所 | A kind of flexible sensor, preparation method and application method |
| CN110375895A (en) * | 2019-07-18 | 2019-10-25 | 浙江大学 | Multi-functional Grazing condition finger print touch sensor |
| CN110763378A (en) * | 2019-11-01 | 2020-02-07 | 浙江大学 | Wearable flexible touch force sensor |
| CN110987246A (en) * | 2019-12-17 | 2020-04-10 | 浙江清华柔性电子技术研究院 | Flexible sensor and preparation and use methods thereof |
Non-Patent Citations (1)
| Title |
|---|
| 喷印柔性压力传感器试验研究;罗毅辉;《机械工程学报》;20190630;第55卷(第11期);第90-97页 * |
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