A flexible and stretchable wireless communication device and preparation method thereof

Abstract

The present invention discloses a flexible and stretchable wireless communication device and its preparation method. The wireless communication device comprises: a flexible inner core; a flexible membrane wrapped around the outer surface of the flexible inner core to form a sealed area with the outer periphery of the flexible inner core, the sealed area being filled with liquid metal; a wireless communication unit located within the flexible inner core; and a communication channel located between the flexible membrane and the flexible inner core, corresponding to the position of the wireless communication unit. By filling the flexible and stretchable wireless communication device with liquid metal to create an airtight seal, the present invention enables the wireless communication device to operate stably and safely under specific operating conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of communication devices, and in particular to a flexible and stretchable wireless communication device and a preparation method thereof. Background Art

[0002] The increasing demand for smart living has driven the rapid development of modern wearable electronics. Various intelligent, flexible, and stretchable electronic components and integrated electronic products are constantly emerging, such as flexible displays, flexible sensors, electronic skin, and soft medical devices.

[0003] Among them, flexible and stretchable wireless communication devices have great development potential. Some wireless communication devices need to work stably in a specific working environment, so good packaging technology and packaging design are required to adapt to the specific working environment.

[0004] To ensure the flexibility and stretchability of the device, current packaging systems are all elastomer packaging. For example, patent CN105631508A provides a stretchable wireless device, which includes an adhesive layer and a shear circuit layer. The shear circuit layer includes a supporting bottom layer with one or more openings on the adhesive layer. The openings in the supporting bottom layer are set to make the shear circuit layer shearable, stretchable, and breathable. The conductive circuit is embedded in the supporting bottom layer, and the semiconductor chip is connected to the conductive circuit. The elastic layer is above the shear circuit layer. The semiconductor chip and the conductive circuit can communicate wirelessly with external devices. Although this solution can achieve the effect of wireless communication, due to the high air permeability of the elastomer, this method has the problem of water, oxygen, and air permeability, which seriously affects the normal operation of the flexible and stretchable wireless communication device.

[0005] Therefore, exploring and designing a device that has both flexible and stretchable properties and wireless communication functions to ensure good sealing performance under specific environments is a technical problem that needs to be urgently solved in this field. Summary of the Invention

[0006] The present invention provides a flexible and stretchable wireless communication device and its preparation method. The wireless communication device comprises a flexible inner core, a flexible membrane covering the flexible inner core, a wireless communication unit placed on the flexible inner core, and a communication channel for transmitting battery signals. Liquid metal is filled between the flexible membrane and the flexible inner core to provide a seal. By filling the flexible and stretchable wireless communication device with liquid metal to provide an airtight seal, the present invention enables the wireless communication device to operate stably and safely in specific operating environments.

[0007] In a first aspect, the present invention provides a flexible and stretchable wireless communication device, comprising:

[0008] Flexible inner core;

[0009] A flexible diaphragm is wrapped around the outside of the flexible inner core and forms a sealing area with the outer periphery of the flexible inner core, and the sealing area is filled with liquid metal;

[0010] a wireless communication unit located in the flexible inner core;

[0011] The communication channel is located between the flexible membrane and the flexible inner core, and corresponds to the position of the wireless communication unit.

[0012] Furthermore, the communication channel includes a barrier piece, which corresponds to the position of the wireless communication unit and blocks the liquid metal in the sealing area from covering the wireless communication unit. The wireless communication unit receives and / or transmits electromagnetic signals through the barrier piece.

[0013] Furthermore, a rigid support array fixed to the flexible diaphragm is provided in the sealing area.

[0014] Furthermore, the rigid support array is a rigid support body arranged in an array pattern, and the shape of the rigid support body is at least one of a sphere, an ellipsoid, a cylinder, a cube, and a cuboid.

[0015] Furthermore, the rigid support body is in the shape of a sphere, the diameter d of the sphere is 0.01-1 mm, and the spacing H between adjacent spheres is: 0≤H≤10d.

[0016] Furthermore, the material of the flexible inner core and the flexible membrane is at least one of rubber and gel; the liquid metal is one of gallium-based liquid metal, indium-based liquid metal, and bismuth-based liquid metal.

[0017] In a second aspect, the present invention further provides a method for preparing the above-mentioned wireless communication device, comprising the following steps:

[0018] preparing a flexible inner core and a flexible membrane;

[0019] Arranging the wireless communication unit in the flexible inner core to form a communication channel;

[0020] Fixing the flexible diaphragm and the flexible inner core to form a sealing area;

[0021] The sealed space is filled with liquid metal to obtain a wireless communication device.

[0022] Furthermore, the flexible diaphragm is fixed with a rigid support;

[0023] Before the flexible diaphragm and the flexible inner core are fixed to form a sealing area, the following steps are included:

[0024] A) Apply heat-release tape to the bottom of the screen, where the diameter of a single hole in the screen is not less than the size of the rigid support;

[0025] B) The rigid support is poured from the top of the screen, passes through the single hole of the screen, and adheres to the heat release tape to form an array pattern;

[0026] C) Apply glue of the same material to the flexible membrane;

[0027] D) placing the heat release tape of step B) on the flexible film of step C);

[0028] E) heating the flexible film after step D) to complete the transfer and attachment of the supporting array pattern from the heat release tape to the flexible film.

[0029] Furthermore, in step E), heating the flexible membrane after step D) specifically includes the following steps:

[0030] Curing was carried out in an oven at 60-80°C for 40-90 minutes, after which the oven temperature was raised to above 100°C.

[0031] Furthermore, the sealing space is filled with liquid metal, which specifically includes the following steps:

[0032] A liquid inlet for filling liquid metal is provided on the flexible diaphragm;

[0033] A culture dish with a hole on the bottom is attached to the liquid inlet of the flexible membrane and placed in a vacuum device;

[0034] Pour the liquid metal into a petri dish;

[0035] Evacuate the vacuum device for 1-2 hours, then increase the pressure to atmospheric pressure;

[0036] Remove the liquid metal from the culture dish and the outer surface of the flexible membrane, and seal the liquid inlet.

[0037] The present invention has at least the following beneficial effects:

[0038] (1) By placing the wireless communication unit in the flexible inner core, the flexible membrane and the liquid metal, and utilizing the low air permeability of the liquid metal itself, the wireless communication unit can be airtightly sealed, thereby enabling the flexible and stretchable wireless communication device to operate stably in a specific working environment.

[0039] (2) By setting up the barrier sheet, liquid metal can be prevented from covering the wireless communication unit, resulting in a shielding effect on the wireless communication unit, providing a channel for the wireless communication unit to perform wireless communication, and ensuring that it can realize the wireless communication function of the device itself under the premise of having good sealing performance.

[0040] (3) The flexible inner core and the flexible diaphragm are supported by a rigid support array, which can prevent the flexible diaphragm and the flexible inner core from being attached to each other when the wireless communication device is in a deformed state (such as stretching, compression, torsion, bending, etc.), thereby preventing the sealing performance of the attached parts from being reduced, thereby ensuring the stretchability of the entire packaging system based on liquid metal. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of a flexible and stretchable wireless communication device provided by the present invention;

[0042] Figure 2 A schematic structural diagram of a rigid support body according to an embodiment of the present invention;

[0043] Figure 3 A schematic diagram of a process for fixing a rigid support body according to an embodiment of the present invention;

[0044] Figure 4A This is a graph showing the test results of water permeation flux of an embodiment provided by the present invention;

[0045] Figure 4B The test results of oxygen permeation flux of the embodiment provided by the present invention are shown in FIG.

[0046] Figure 5 This is a schematic diagram of a wireless communication performance testing process according to an embodiment of the present invention.

[0047] Description of reference numerals:

[0048] 1-flexible inner core, 2-flexible membrane, 21-first flexible membrane, 22-second flexible membrane, 3-wireless communication unit, 4-barrier sheet, 5-rigid support array, 51-rigid support body, 6-fixed sheet group, 7-liquid inlet, 8-RFID electronic tag, 9-RFID reader, 100-wireless communication device. DETAILED DESCRIPTION

[0049] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0050] In actual application scenarios, due to the functions of the wireless communication unit itself, its application is relatively wide. There are cases where the wireless communication unit needs to be applied to a specific working environment. Therefore, it not only needs to have good airtight sealing performance, but also needs to have good flexibility and stretchability. Figure 1 As shown, the present invention provides a flexible and stretchable wireless communication device, comprising:

[0051] Flexible inner core 1;

[0052] A flexible diaphragm 2 is wrapped around the outside of the flexible inner core 1 and forms a sealed area with the outer periphery of the flexible inner core 1. The sealed area is filled with liquid metal. The material of the flexible inner core 1 and the flexible diaphragm 2 is at least one of rubber and gel. The liquid metal is one of gallium-based liquid metal, indium-based liquid metal, and bismuth-based liquid metal.

[0053] a wireless communication unit 3, which is located in the flexible inner core 1;

[0054] The communication channel is located between the flexible membrane 2 and the flexible inner core 1 , and corresponds to the position of the wireless communication unit 3 .

[0055] The present invention designs a flexible and stretchable wireless communication device by placing a wireless communication unit 3 within a flexible inner core 1, a flexible membrane 2, and liquid metal. This allows the wireless communication unit 3 to function as a wireless communication device. Because the flexible inner core 1, the flexible membrane 2, and the liquid metal all possess good stretchability, the overall wireless communication device also possesses good stretchability. Furthermore, the low permeability of the liquid metal, coupled with its stretchability, allows for a hermetic seal within the wireless communication device, resulting in the device being both stretchable and hermetic.

[0056] In order to ensure that the wireless communication unit 3 still maintains the original signal transmission effect and is not shielded by the filled liquid metal, a communication channel is set to enable the wireless communication unit 3 to receive and / or transmit electromagnetic signals.

[0057] The communication channel may include a barrier sheet 4 positioned between the flexible inner core 1 and the flexible membrane 2. The barrier sheet 4 is positioned to correspond to the wireless communication unit 3, preventing liquid metal from covering the wireless communication unit 3 within the sealed area. The wireless communication unit 3 receives and / or transmits electromagnetic signals through the barrier sheet 4. The barrier sheet 4 prevents the liquid metal from shielding the wireless communication unit 3, providing a channel for wireless communication for the wireless communication unit 3, ensuring that the wireless communication function can be realized while maintaining good sealing performance. Furthermore, the barrier sheet 4 not only enables signal transmission from the wireless communication unit 3 but also provides support for the flexible inner core 1 and the flexible membrane 2, preventing the adhesion between the flexible inner core 1 and the flexible membrane 2 from affecting the airtight sealing performance. To ensure better support for the wireless communication channel provided by the barrier sheet 4, both the barrier sheet 4 and the wireless communication unit 3 can be positioned in the middle of the flexible inner core 1. The dimensions of the barrier sheet 4 can be designed to correspond to the dimensions of the wireless communication unit 3; for example, the dimensions of the barrier sheet 4 can be greater than or equal to those of the wireless communication unit 3. In some cases, for example, when a good flexible and stretchable effect is required but a strong electromagnetic signal is not required, the size of the barrier sheet 4 can be appropriately reduced, that is, the size of the barrier sheet 4 can be smaller than the size of the wireless communication unit 3. In addition, to ensure that the barrier sheet 4 has good sealing performance when providing a channel for wireless communication of the wireless communication unit 3, the barrier sheet 4 can be selected carefully. In actual application scenarios, the barrier sheet 4 is made of a rigid insulating material; preferably, the barrier sheet 4 is a glass sheet.

[0058] When the wireless communication device is suitable for communication in a specific environment, in order to ensure that the wireless communication device still has a good airtight sealing effect when it is bent and / or stretched, a rigid support array 5 fixed to the flexible diaphragm 2 is set in the sealing area. The rigid support array 5 is a rigid support body 51 arranged in an array pattern, and the shape of the rigid support body 51 is at least one of a sphere, an ellipsoid, a cylinder, a cube, and a cuboid.

[0059] like Figure 2As shown, the array structure formed by the rigid support body 51 can ensure that the space between the flexible inner core 1 and the flexible membrane 2 is always filled with liquid metal when the wireless communication device is bent and / or stretched, that is, the flexible inner core 1 and the flexible membrane 2 do not contact each other. Furthermore, in order to minimize the impact of the rigid support body 51 on the flexible and stretchable properties of the wireless communication device, the rigid support body 51 can be a sphere. Due to the curved surface structure of the sphere itself, the contact area between the rigid support body 51 and the flexible inner core 1 and / or the flexible membrane 2 can be minimized. Moreover, due to the curved surface structure, when the wireless communication device is bent and / or stretched, the force exerted by the rigid support body 51 on the flexible inner core 1 and / or the flexible membrane 2 can be prevented from causing stress concentration. This can ensure the integrity of the flexible inner core 1 and / or the flexible membrane 2 and prevent damage to the flexible inner core 1 and / or the flexible membrane 2, which can lead to leakage of liquid metal. Therefore, the sealing effect can be improved to a certain extent. The diameter d of the sphere is 0.01-1mm, and the spacing H between adjacent spheres is: 0≤H≤10d. By limiting the size and spacing of the spheres, it is possible to avoid large spacing between adjacent spheres, which could prevent the flexible core 1 and flexible membrane 2 from contacting each other when the wireless communication device between adjacent spheres bends and / or stretches. Therefore, the spacing between adjacent spheres is limited based on the sphere diameter to ensure good support and airtight sealing. Furthermore, the spacing H between adjacent spheres satisfies the following: 0 ≤ H ≤ 10 d. This means that the spacing between adjacent spheres within the rigid support array 5 varies between 0 and 10 d, meaning that adjacent spheres can have spacings of 5 d or 10 d at the same time. Alternatively, all adjacent spheres within the rigid support array 5 can have the same spacing, selected within the range of 0-10 d. More preferably, the sphere diameter d is 0.3 mm, and the spacing H between adjacent spheres satisfies the following: 0 ≤ H ≤ 0.7 d.

[0060] In addition, in order to facilitate the preparation of the wireless communication device and to combine and fix the flexible inner core 1 and the flexible membrane 2, the flexible membrane 2 can be set as a first flexible membrane 21 and a second flexible membrane 22. When the flexible membrane 2 forms a sealed interval with the outer periphery of the flexible inner core 1, the first flexible membrane 21 and the second flexible membrane 22 are sealed and fixed on all sides. At the same time, the first flexible membrane 21 and the second flexible membrane 22 can also be partially or completely fixed on all sides to the flexible inner core 1. Therefore, after the fixation is completed, the sealed intervals formed by the first flexible membrane 21 and the second flexible membrane 22 with the flexible inner core 1 can be connected or not connected to each other. When the two sealed intervals formed by the first flexible membrane 21 and the second flexible membrane 22 with the flexible inner core 1 are connected to each other, a liquid inlet 7 can be opened on the first flexible membrane 21 or the second flexible membrane 22, so that all sealed intervals are filled with liquid metal. Of course, the liquid inlet 7 can also be set at the connection position between the first flexible membrane 21 and the second flexible membrane 22. When the two sealed areas formed by the first flexible diaphragm 21 and the second flexible diaphragm 22 are not connected to the flexible inner core 1, liquid inlets 7 are respectively opened on the first flexible diaphragm 21 and the second flexible diaphragm 22 to achieve liquid metal filling of the two unconnected sealed areas.

[0061] When the wireless communication device is in a flexible and stretchable state, to provide a gripping, stretching, and / or bending position, a set of airtight, rigid fixing plates 6 can be provided on either side of the flexible inner core 1. Each fixing plate set 6 includes fixing plates located at either end of the flexible inner core 1. The side surfaces of the fixing plates are respectively bonded and fixed to the flexible inner core 1 and the flexible membrane 2, thereby forming a gripping position with the flexible inner core 1 and the flexible membrane 2. This gripping position serves as a fulcrum for stretching and / or bending the wireless communication device. Preferably, the fixing plates are made of glass.

[0062] The flexible inner core 1 and flexible membrane 2 are made of at least one of rubber and gel; the liquid metal is one of gallium-based liquid metal, indium-based liquid metal, and bismuth-based liquid metal. More specifically, the flexible inner core 1 and flexible membrane 2 are made of silicone rubber (cross-linked polydimethylsiloxane (PDMS), aliphatic aromatic random copolyester (Ecoflex), natural rubber, butyl rubber, nitrile rubber, chlorobutyl rubber, neoprene, fluororubber, butadiene rubber, polyurethane or other synthetic rubber, ion gel, hydrogel, or other stretchable elastic layer.

[0063] The liquid metal is at least one of metal gallium, gallium-indium alloy, gallium-aluminum alloy, gallium-zinc-gold alloy, gallium-silver alloy, gallium-indium-tin alloy, gallium-indium-tin-zinc alloy or other gallium-based liquid metals, or indium-bismuth alloy, indium-tin alloy, indium-tin-bismuth alloy, bismuth-lead-tin-cadmium alloy, bismuth-lead-tin-cadmium-indium alloy and other liquid materials with metallic bonds.

[0064] The present invention also provides a method for preparing a wireless communication device, comprising the following steps:

[0065] Prepare a flexible inner core 1 and a flexible membrane 2;

[0066] Arrange the wireless communication unit 3 in the flexible inner core 1 to form a communication channel;

[0067] Fix the flexible membrane 2 and the flexible inner core 1 to form a sealing area;

[0068] A liquid inlet 7 for filling liquid metal is provided on the flexible diaphragm 2;

[0069] Glue the culture dish with holes on the bottom to the liquid inlet 7 of the flexible membrane 2 and place it in the vacuum device;

[0070] Pour the liquid metal into a petri dish;

[0071] Evacuate the vacuum device for 1-2 hours, then increase the pressure to atmospheric pressure;

[0072] The liquid metal on the outer surface of the culture dish and the flexible membrane 2 is removed, and the liquid inlet 7 is sealed to obtain a wireless communication device.

[0073] The preparation of the flexible inner core 1 and the flexible membrane 2 includes:

[0074] Using an infrared laser cutting system to cut a polymethyl methacrylate sheet with appropriate thickness into a preset shape;

[0075] The cut polymethyl methacrylate sheets were bonded together using chloroform to form a polymethyl methacrylate mold;

[0076] The uncured mixed solution is poured into a polymethyl methacrylate mold, wherein the mixed solution is composed of a flexible material (polydimethylsiloxane) and a curing agent in a weight ratio of (5-10): (1-2);

[0077] After vacuum degassing, the excess mixed solution was scraped off the polymethyl methacrylate mold;

[0078] The mold containing the mixed solution is placed in an oven at 70-90° C. for 1-2 hours to complete curing, thereby obtaining a flexible inner core 1 or a flexible membrane 2 .

[0079] like Figure 3 As shown, the flexible membrane 2 of the present invention is fixed with a rigid support body 51; before the flexible membrane 2 and the flexible inner core 1 are fixed to form a sealed area, the following steps are also included:

[0080] A) applying heat release tape to the bottom of the screen, wherein the diameter of a single hole of the screen is not less than the size of the rigid support 51;

[0081] B) The rigid support 51 is poured from the top of the screen, passes through the single hole of the screen and adheres to the heat release tape to form an array pattern;

[0082] C) Apply glue of the same material to the flexible membrane 2;

[0083] D) placing the heat release tape of step B) on the flexible film 2 of step C);

[0084] E) Curing the flexible film 2 after step D) in an oven at 60-80° C. for 40-90 min, then raising the oven temperature to above 100° C. until the supporting array pattern is completely transferred from the thermal release tape to the flexible film 2 .

[0085] exist Figure 3 In the states shown, a shows the thermal release tape attached to the bottom of the screen, b shows the rigid support being poured from the top of the screen, c shows the rigid support adhering to the thermal release tape to form an array pattern, d shows the flexible membrane being coated with glue of the same material, e shows the thermal release tape being placed on the flexible membrane with the array pattern facing the glue, and f shows the array pattern being transferred and attached to the flexible membrane. In actual application scenarios, the steps are: a → b → c + d → e → f.

[0086] The preparation method of the present invention includes the following embodiments:

[0087] Example 1

[0088] A method for preparing a wireless communication device comprises the following steps:

[0089] A flexible inner core and a flexible membrane are prepared; a wireless communication unit is arranged in the flexible inner core to form a communication channel; the flexible membrane and the flexible inner core are fixed to form a sealed area; a liquid inlet for filling liquid metal is opened on the flexible membrane; a culture dish with a hole on the bottom is attached to the liquid inlet position of the flexible membrane and placed in a vacuum device; liquid metal is poured into the culture dish; the vacuum device is evacuated for 1 hour and then the pressure is increased to atmospheric pressure; the liquid metal on the outer surface of the culture dish and the flexible membrane is removed, the liquid inlet is sealed, and a wireless communication device is obtained.

[0090] (1) Preparation of flexible inner core and flexible membrane.

[0091] Using an infrared laser cutting system to cut a polymethyl methacrylate sheet with an appropriate thickness into a preset shape; using chloroform to bond the cut polymethyl methacrylate sheets together to form a polymethyl methacrylate mold;

[0092] The uncured mixed solution is poured into a polymethyl methacrylate mold, wherein the mixed solution comprises a flexible material (polydimethylsiloxane) and a curing agent in a weight ratio of 5:1; after vacuum degassing, the excess mixed solution is scraped off from the polymethyl methacrylate mold;

[0093] The mold containing the mixed solution is placed in an oven at 80° C. for 1 hour to complete curing, thereby obtaining a flexible inner core or a flexible membrane.

[0094] (2) Preparation of rigid support array.

[0095] Before the flexible diaphragm and the flexible inner core are fixed to form a sealing area, the method further includes:

[0096] A) Apply heat-release tape to the bottom of a 0.4 mm pore size sieve.

[0097] B) A rigid support with a diameter of 0.3 mm is poured from the top of the screen, passes through the mesh of the screen, and adheres to the heat release tape to form an array pattern;

[0098] C) Apply glue of the same material to the flexible membrane;

[0099] D) placing the heat release tape of step B) on the flexible film of step C);

[0100] E) Curing the flexible film after step D) in an oven at 80° C. for 60 min, then raising the oven temperature to 100° C. until the supporting array pattern is completely transferred from the thermal release tape to the flexible film.

[0101] Example 2

[0102] A method for preparing a wireless communication device comprises the following steps:

[0103] A flexible inner core and a flexible membrane are prepared; a wireless communication unit is arranged in the flexible inner core to form a communication channel; the flexible membrane and the flexible inner core are fixed to form a sealed area; a liquid inlet for filling liquid metal is opened on the flexible membrane; a culture dish with a hole on the bottom is attached to the liquid inlet position of the flexible membrane and placed in a vacuum device; liquid metal is poured into the culture dish; the vacuum device is evacuated for 2 hours and then the pressure is increased to atmospheric pressure; the liquid metal on the outer surface of the culture dish and the flexible membrane is removed, the liquid inlet is sealed, and a wireless communication device is obtained.

[0104] (1) Preparation of flexible inner core and flexible membrane.

[0105] Using an infrared laser cutting system to cut polymethyl methacrylate sheets with appropriate thickness into specific shapes;

[0106] The cut polymethyl methacrylate sheets were bonded together using chloroform to form a polymethyl methacrylate mold;

[0107] The uncured mixed solution is poured into a polymethyl methacrylate mold, wherein the mixed solution consists of a flexible material (polydimethylsiloxane) and a curing agent in a weight ratio of 11:2;

[0108] After vacuum degassing, the excess mixed solution was scraped off the polymethyl methacrylate mold;

[0109] The mold containing the mixed solution is placed in an oven at 90° C. for 1 hour to complete the curing, thereby obtaining a flexible inner core or a flexible membrane.

[0110] (2) Preparation of rigid support array.

[0111] Before the flexible diaphragm and the flexible inner core are fixed to form a sealing area, the method further includes:

[0112] A) Apply heat-release tape to the bottom of a 1 mm sieve.

[0113] B) A rigid support with a diameter of 0.8 mm is poured from the top of the screen, passes through the mesh of the screen, and adheres to the heat release tape to form an array pattern;

[0114] C) Apply glue of the same material to the flexible membrane;

[0115] D) placing the heat release tape of step B) on the flexible film of step C);

[0116] E) Curing the flexible film from step D) in an oven at 60° C. for 90 minutes, then raising the oven temperature to 140° C. until the supporting array pattern is completely transferred from the thermal release tape to the flexible film.

[0117] Example 3

[0118] A method for preparing a wireless communication device comprises the following steps:

[0119] A flexible inner core and a flexible membrane are prepared; a wireless communication unit is arranged in the flexible inner core to form a communication channel; the flexible membrane and the flexible inner core are fixed to form a sealed area; a liquid inlet for filling liquid metal is opened on the flexible membrane; a culture dish with a hole on the bottom is attached to the liquid inlet position of the flexible membrane and placed in a vacuum device; liquid metal is poured into the culture dish; the vacuum device is evacuated for 1 hour and then the pressure is increased to atmospheric pressure; the liquid metal on the outer surface of the culture dish and the flexible membrane is removed, the liquid inlet is sealed, and a wireless communication device is obtained.

[0120] (1) Preparation of flexible inner core and flexible membrane.

[0121] Using an infrared laser cutting system to cut polymethyl methacrylate sheets with appropriate thickness into specific shapes;

[0122] The cut polymethyl methacrylate sheets were bonded together using chloroform to form a polymethyl methacrylate mold;

[0123] The uncured mixed solution is poured into a polymethyl methacrylate mold, wherein the mixed solution consists of a flexible material (polydimethylsiloxane) and a curing agent in a weight ratio of 10:1;

[0124] After vacuum degassing, the excess mixed solution was scraped off the polymethyl methacrylate mold;

[0125] The mold containing the mixed solution was placed in an oven at 70° C. for 1 hour to complete the curing, thereby obtaining a flexible inner core or a flexible membrane.

[0126] (2) Preparation of rigid support array.

[0127] Before the flexible diaphragm and the flexible inner core are fixed to form a sealing area, the method further includes:

[0128] A) Apply heat-release tape to the bottom of a 0.6 mm sieve.

[0129] B) A rigid support with a diameter of 0.5 mm is poured from the top of the screen, passes through the mesh of the screen, and adheres to the heat release tape to form an array pattern;

[0130] C) Apply glue of the same material to the flexible membrane;

[0131] D) placing the heat release tape of step B) on the flexible film of step C);

[0132] E) curing the flexible film from step D) in an oven at 70° C. for 80 min, and then raising the oven temperature to 100° C. until the supporting array pattern is completely transferred from the thermal release tape to the flexible film.

[0133] Comparative Example:

[0134] On the basis of Example 1, the step of injecting liquid metal into the sealed area through the liquid inlet is omitted, and a wireless communication device not filled with liquid metal is prepared.

[0135] Performance testing:

[0136] The wireless communication devices prepared in the above embodiments and comparative examples were tested for device performance.

[0137] Water and oxygen transmission rate testing of liquid metal and flexible materials (PDMS, polydimethylsiloxane):

[0138] Preparation method of test sample for water permeability of wireless communication device: After two flexible membranes, a flexible inner core and a glass sheet with a thickness of 0.33mm and a hole in the center are treated by UV ozone cleaning machine (YZUV-22C, KenuoInstrument) for 1 minute, the two flexible membranes made of flexible materials, the flexible inner core, the wireless communication unit, the barrier sheet and the glass sheet are stacked together and placed in an 80℃ oven for 1 hour to produce adhesion. The hole in the center of the glass sheet is prepared by an infrared laser cutting system (BF1309+); the two flexible membranes are bonded to the top and bottom surfaces of the glass sheet respectively to form a cavity, and the glass The glass sheet corresponds to the position of the wireless communication unit and the barrier sheet; a culture dish with a hole on the bottom is pasted to the top flexible membrane with a liquid metal inlet; after pouring the liquid metal into the culture dish, the entire sample is placed in a container and vacuumed for 1 hour to remove the air in the prepared chamber; the vacuum of the container is broken, and the pressure inside the container gradually returns to atmospheric pressure, resulting in a pressure difference between the container and the prepared chamber, which drives the liquid metal to quickly enter the chamber through the liquid metal inlet; the culture dish and excess liquid metal are removed, and the liquid metal inlet is covered with uncured flexible material (PDMS); and the flexible material is cured.

[0139] The sample prepared by the above test method is used to measure the water permeability; the radius of the circular liquid metal film is about 11.00mm, and its area is 379.94mm 2 The radius of the central hole in the glass is about 8.46 mm, and its area is 224.79 mm 2 The thickness of the liquid metal film is 1.33 mm.

[0140] Sample for oxygen transmission rate measurement: The fabrication process for this sample is similar to that for water transmission rate measurement. A cavity designed to support liquid metal is used for oxygen transmission rate measurement. The radius of the circular opening is larger (~30 mm), and the thickness of the liquid metal film is reduced to ~0.5 mm.

[0141] Measurement of water and oxygen transmission rate:

[0142] The water flux through the sample was measured using a water vapor transmission rate analyzer (AQUATRAN3, AMETEK MOCON). The temperature during the measurement was set to 25° C. The relative humidity in the chamber on one side of the sample was set to 90%, and the relative humidity in the chamber on the other side was set to 0%.

[0143] Oxygen flux through the sample was measured using an oxygen transmission rate analyzer (OX-TRAN2 / 22H, AMETEK MOCON). The temperature was also set at 25°C. Oxygen was present on one side of the sample, and nitrogen, at the same pressure as oxygen, was present on the other side. The oxygen partial pressure difference between the two sides of the sample was assumed to be 1 standard atmosphere.

[0144] like Figure 4A As shown, after about 94 hours of measurement, the flux of water passing through the sample containing liquid metal reaches a stable value of 4.0*10 -7 cc / day. This value is within the measurement limit of the water vapor transmission rate permeation analyzer ((2.5±2.5)*10 - 7 cc / day). The water vapor permeability coefficient of liquid metal is calculated to be 9.6*10 -21 m 2 / (sPa), which is more than four orders of magnitude smaller than that of flexible materials (PDMS). If a more sensitive instrument is used, the actual water vapor permeability coefficient of liquid metal may be smaller than the measured value.

[0145] like Figure 4B As shown, the oxygen flux through the liquid metal sample reaches 2.5*10 -6 cc / day, which also reached the measurement limit of the oxygen transmission rate analyzer ((2.5±2.5)*10 -6 cc / day). The oxygen permeability coefficient of liquid metal is calculated to be 5.0*10 -23 m 2 / (sPa), which is more than eight orders of magnitude smaller than that of flexible materials (PDMS).

[0146] Wireless communication performance test of wireless communication device based on liquid metal packaging:

[0147] like Figure 5 The wireless communication unit can be an RFID tag (CER1207, 860-960 MHz) and is tested via an external RFID reader (RD906M, 906 MHz). When the RFID reader 9 is connected to the computer, it emits a radio signal. If the RFID tag 8 is not present, no response signal is transmitted back to the RFID reader 9. At this point, only the red LED on the RFID reader 9 lights up, and the corresponding computer screen recording the signal is blank.

[0148] With the introduction of the liquid metal encapsulated wireless communication device 100, communication began between the RFID tag 8 and the RFID reader 9 within the device. Both the red and green LEDs on the reader illuminated, and the computer screen recording the signals displayed the communication signal. Furthermore, experiments conducted by flipping the device so that the communication channel faced downward revealed that communication between the internal RFID tag 8 and the external RFID reader 9 continued. Furthermore, the improved liquid metal encapsulated wireless communication device maintained continuous communication with the RFID reader 9 even under 20% stretching.

[0149] The present invention also fills deionized water containing about 2.8 wt% red dye (Wilton Industries, IL, US) into the flexible inner core of the device through a copper filling tube. The result is that under a 20% stretching state, the device filled with red dye filling liquid can still communicate continuously with an external RFID reader.

[0150] Therefore, through the above tests on wireless communication performance and airtightness performance, it can be concluded that the flexible and stretchable wireless communication device provided by the present invention can, while airtightly sealing the wireless communication unit, ensure that the wireless communication unit installed therein can maintain good communication with the outside world.

[0151] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the invention. Thus, the present invention is intended to include such changes and modifications as fall within the scope of the claims and their equivalents.

Claims

1. A flexible and stretchable wireless communication device, characterized in that: include: Flexible inner core; A flexible diaphragm is wrapped around the outside of the flexible inner core and forms a sealing area with the outer periphery of the flexible inner core, and the sealing area is filled with liquid metal; a wireless communication unit located in the flexible inner core; The communication channel is located between the flexible diaphragm and the flexible inner core, and corresponds to the position of the wireless communication unit; the communication channel includes a barrier piece, which corresponds to the position of the wireless communication unit and blocks the liquid metal in the sealing interval from covering the wireless communication unit. The wireless communication unit receives and / or transmits electromagnetic signals through the barrier piece.

2. The wireless communication device according to claim 1, wherein A rigid support array fixed to the flexible diaphragm is provided in the sealing area.

3. The wireless communication device according to claim 2, wherein The rigid support array is a rigid support body arranged in an array pattern, and the shape of the rigid support body is at least one of a sphere, an ellipsoid, a cylinder, a cube, and a cuboid.

4. The wireless communication device according to claim 3, wherein The rigid support body is in the shape of a sphere, the diameter d of the sphere is 0.01-1 mm, and the distance H between adjacent spheres is: 0≤H≤10d.

5. The wireless communication device according to any one of claims 1 to 4, characterized in that: The material of the flexible inner core and the flexible membrane is at least one of rubber and gel; the liquid metal is one of gallium-based liquid metal, indium-based liquid metal and bismuth-based liquid metal.

6. A method for preparing a wireless communication device according to any one of claims 1 to 5, characterized in that: The following steps are involved: preparing a flexible inner core and a flexible membrane; Arranging the wireless communication unit in the flexible inner core to form a communication channel; Fixing the flexible diaphragm and the flexible inner core to form a sealing area; The sealed space is filled with liquid metal to obtain a wireless communication device.

7. The method for preparing a wireless communication device according to claim 6, wherein: The flexible diaphragm is fixed with a rigid support; Before the flexible diaphragm and the flexible inner core are fixed to form a sealing area, the following steps are included: A) Apply heat release tape to the bottom of the screen. The single hole diameter of the screen should not be less than the size of the rigid support. B) The rigid support is poured from the top of the mesh, passes through the single hole of the mesh, and adheres to the heat release tape to form an array pattern; C) Apply glue of the same material to the flexible membrane; D) placing the thermal release tape from step B) on the flexible film from step C); E) Heating the flexible film after step D) to complete the transfer attachment from the thermal release tape to the flexible film until the supporting array pattern is formed.

8. The method for preparing a wireless communication device according to claim 7, wherein: In step E), heating the flexible membrane after step D) specifically includes the following steps: Curing was carried out in an oven at 60-80°C for 40-90 minutes, after which the oven temperature was raised to above 100°C.

9. The method for preparing a wireless communication device according to claim 6, wherein: Filling the sealed space with liquid metal includes the following steps: A liquid inlet for filling liquid metal is provided on the flexible diaphragm; A culture dish with a hole on the bottom is attached to the liquid inlet of the flexible membrane and placed in a vacuum device; Pour the liquid metal into a petri dish; Evacuate the vacuum device for 1-2 hours, then increase the pressure to atmospheric pressure; Remove the liquid metal from the culture dish and the outer surface of the flexible membrane, and seal the liquid inlet.

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