Preparation method and application of flexible short-distance wireless communication device

Abstract

The invention relates to a preparation method and application of a flexible short-distance wireless communication device. Comprising the steps of preparation of a flexible substrate of the NFC device, design and preparation of a coil structure, and chip installation. The flexible NFC device developed by the patent can carry out short-distance wireless communication with compatible equipment, and has various application scenes, for example, the flexible NFC device carries out short-distance wireless communication with a mobile phone, and when the mobile phone is close to the NFC device, the mobile phone automatically opens a webpage, plays songs, or makes a call, and completes information identification and transmission; the developed NFC device can also be used for opening a door lock. The flexible NFC device can be integrated on a common commodity to form an integrated commodity with a short-distance wireless communication function, and the common commodity is endowed with an intelligent attribute.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communication, and in particular relates to a preparation method and application of a flexible short-range wireless communication device. Background Art

[0002] Near Field Communication (NFC) devices can perform contactless identification and data exchange with compatible devices, and realize short-range wireless communication between mobile terminals such as mobile phones. With the rapid development of the Internet of Things and smart devices, NFC technology has been widely promoted and applied in recent years. Some NFC devices are made on hard substrates such as PCB, but such NFC devices are not flexible, cannot bend, have poor shape adaptability, and cannot be integrated in curved products or wearable devices. Some flexible NFC devices are made on coated paper, polyethylene terephthalate (PET), polyimide (PI), etc., but they have problems of high cost and difficulty in degradation. In addition, daily-use commodities, such as cups, clothes, etc., only have ordinary life use attributes, while future commodities are developing in the direction of multi-function and intelligence. Therefore, it is of great significance to give ordinary commodities wireless communication functions. Summary of the invention

[0003] In view of the above problems, the present invention prepares a low-cost, flexible short-range wireless communication (NFC) device, uses waste cotton cloth / cotton as raw materials to prepare a flexible substrate of the NFC device, and designs the structure and coil routing of the NFC device to enable it to have a wireless communication function and simplify the manufacturing process. The prepared flexible NFC device can perform close-range wireless communication with compatible devices (mobile phones, door locks, etc.). In addition, this patent also integrates this flexible NFC device into ordinary commodities to form an integrated commodity with a short-range wireless communication function, giving ordinary commodities intelligent attributes, making our lifestyle more convenient and intelligent. The flexible NFC device developed by this patent can be applied to a variety of scenarios and has important practical value.

[0004] The object of the present invention is to provide a method for preparing a flexible near field wireless communication (NFC) device.

[0005] Another purpose of the present invention is to apply the NFC device to compatible devices (mobile phones, door locks, etc.) for short-range wireless communication and to integrate the NFC device on the surface of various objects to prepare intelligent products.

[0006] The object of the present invention is achieved through the following solutions:

[0007] A method for preparing a flexible near field wireless communication (NFC) device, comprising the following steps:

[0008] (1) Converting waste cotton cloth or cotton into nano-sized fibers using an oxidizing agent;

[0009] (2) assembling the nano-sized fibers obtained in step (1) into a flexible film;

[0010] (3) Design the number of coils, coil line width, coil thickness, spacing between adjacent coils, and coil length of the NFC device;

[0011] (4) printing a coil circuit on the flexible film obtained in step (2) according to the coil parameters designed in step (3);

[0012] (5) An NTAG chip is installed on the coil circuit printed in step (4). The terminal end of the coil circuit is connected to the chip by punching a hole in the substrate and printing a circuit from the back of the substrate to form a closed loop, thereby obtaining a flexible short-range wireless communication device NFC.

[0013] In step (1), the oxidizing agent is a combination of 2,2,6,6-tetramethylpyridine-1-oxyl free radical TEMPO, sodium bromide NaBr, and sodium hypochlorite NaClO; and the mass ratio of waste cotton cloth or cotton, TEMPO, NaBr and NaClO is 12: (0.1-0.7): (1.0-7): (50-350).

[0014] In step (3), the number of coil turns, the line width of the coil, the spacing between adjacent coils, and the thickness of the coil of the NFC device are: 11-14, 0.4-0.7 mm, 0.2-0.5 mm, and 70 μm, respectively; the size of the outermost coil is: 40 mm long × 24 mm wide.

[0015] In step (4), the material used to print the coil circuit is silver or copper-based conductive paste.

[0016] The present invention provides a flexible near-field wireless communication (NFC) device product, which is prepared according to the above method and has a near-field wireless communication function.

[0017] The flexible short-distance wireless communication device prepared by the present invention is used in the application of short-distance wireless communication. The steps are:

[0018] (1) Content or instructions are written on the chip of the flexible short-range wireless communication device, so that short-range wireless communication with the compatible device is achieved when the compatible device is close.

[0019] In step (1), the compatible devices include but are not limited to: mobile phones and smart door locks.

[0020] Furthermore, NFC devices for writing content or instructions are integrated into ordinary commodities to form integrated commodities with short-range wireless communication functions, thus giving ordinary commodities intelligent attributes.

[0021] Application 1: Application of the NFC device product of the present invention and a mobile phone for close range wireless communication, the specific steps are as follows:

[0022] (1) Use the NFC app on a mobile phone to write instructions (such as a website, song, or phone number) into the NFC device product of the present invention;

[0023] (2) When the NFC device product with the instructions written in step (1) is placed close to a mobile phone, the mobile phone automatically opens a web page, plays a song, or makes a call, completing the recognition and transmission of information;

[0024] Application 2: Using the NFC device product of the present invention to open a smart door lock, the specific steps are as follows:

[0025] (1) Place the NFC device product of the present invention close to the NFC identification area of ​​the door lock, and use the mobile phone door lock app to complete the verification and adding process;

[0026] (2) When the NFC device product that has completed verification in step (1) is brought close to the smart door lock, the door lock is opened.

[0027] Application 3: Integrate this NFC device product on the surface of various objects to prepare intelligent products. The specific steps are as follows:

[0028] (1) Bonding the NFC device to the surface of the object;

[0029] (2) Use the NFC app on your phone to write commands (e.g., songs) into the NFC device.

[0030] (3) When a mobile phone is placed close to the NFC device of the above-mentioned items, the mobile phone automatically plays a song, making ordinary items intelligent;

[0031] The method of bonding and fusing the NFC device to the surface of the object includes: a. fixing and fusing the NFC device to the surface of the object with tape / adhesive; or b. wetting the surface of the object with water or water / ethanol, placing the NFC device on the surface of the object, and after natural drying, the NFC device is fused to the object, wherein the materials of the objects include: glass, paper, PVA, cellulose, and other materials that can be bonded and fused with the NFC device when wetted with water or water / ethanol.

[0032] Beneficial effects of the present invention:

[0033] (1) The NFC device substrate made of waste cotton cloth or cotton in the present invention has the characteristics of flexibility, degradability and low cost.

[0034] (2) The flexible near-field wireless communication (NFC) device product obtained by the present invention has a near-field wireless communication function; by writing content / instructions on the NFC device, near-field wireless communication with compatible devices can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The near field wireless communication (NFC) device prepared in Example 2, (a) the front side of the NFC device; (b) the back side of the NFC device;

[0036] Figure 2 When the NFC device with the URL command written is close to the mobile phone, the mobile phone automatically opens the written URL / webpage picture;

[0037] Figure 3 Application for opening smart door locks for NFC devices;

[0038] Figure 4 The NFC device is integrated with the glass, and the song will be played automatically when the phone is close to it;

[0039] Figure 5 The NFC device is integrated into the clothing and automatically calls the emergency contact when the mobile phone is close. DETAILED DESCRIPTION

[0040] Example 1

[0041] Preparation of flexible near field communication (NFC) devices:

[0042] Step 1) 12g cotton or waste cotton, 15ml 1wt% 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) aqueous solution and 15ml 10wt% NaBr aqueous solution are dispersed in 700ml deionized water using a stirrer. 80g NaClO is slowly added to the mixed solution. During this process, NaOH is used to adjust the pH value of the solution to a pH value between 9 and 11. After the reaction is completed, the obtained nano-sized cotton or waste cotton fibers are filtered to form a flexible film.

[0043] Step 2) Print a conductive coil on a flexible film, the number of coils, the line width of the coil, the spacing between adjacent coils, and the thickness of the coil are 11, 0.5 mm, 0.2 mm, and 70 μm, respectively. The dimensions of the outermost coil are 40 mm long and 24 mm wide. The material used to print the coil is a silver-based conductive paste.

[0044] Step 3) Install the chip. One end of the chip is connected to the starting section of the coil. A hole is punched on the substrate at the other end of the chip and the end of the coil circuit. At the hole position, a circuit is printed from the back of the substrate to connect the other end of the chip and the end of the coil circuit to form a closed loop, and a flexible NFC device is obtained.

[0045] Example 2

[0046] Preparation of flexible near field communication (NFC) devices:

[0047] Step 1) 12g cotton or waste cotton cloth, 20ml 1wt% 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) aqueous solution and 20ml 10wt% NaBr aqueous solution are dispersed in 700ml deionized water using a stirrer. 100g NaClO is slowly added to the mixed solution. During this process, NaOH is used to adjust the pH value of the solution to a value between 9 and 11. After the reaction is completed, the obtained nano-sized cotton or waste cotton cloth fibers are filtered to form a flexible film.

[0048] Step 2) Print a conductive coil on a flexible film. The number of coils, the line width of the coil, the spacing between adjacent coils, and the thickness of the coil are 12, 0.5 mm, 0.3 mm, and 70 μm, respectively. The dimensions of the outermost coil are 40 mm long and 24 mm wide. The material used to print the coil is a silver-based conductive paste.

[0049] Step 3) Install the chip. One end of the chip is connected to the starting section of the coil. A hole is punched on the substrate at the other end of the chip and the end of the coil circuit. At the hole position, a circuit is printed from the back of the substrate to connect the other end of the chip and the end of the coil circuit to form a closed loop, and a flexible NFC device is obtained.

[0050] Example 3

[0051] Preparation of flexible near field communication (NFC) devices:

[0052] Step 1) 12g cotton or waste cotton, 30ml 1wt% 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) aqueous solution and 25ml 10wt% NaBr aqueous solution are dispersed in 700ml deionized water using a stirrer. 150g NaClO is slowly added to the mixed solution. During this process, NaOH is used to adjust the pH value of the solution to a value between 9 and 11. After the reaction is completed, the obtained nano-sized cotton or waste cotton fibers are filtered to form a flexible film.

[0053] Step 2) Print a conductive coil on a flexible film. The number of coils, the line width of the coil, the spacing between adjacent coils, and the thickness of the coil are 11, 0.4 mm, 0.3 mm, and 70 μm, respectively. The dimensions of the outermost coil are 40 mm long and 24 mm wide. The material used to print the coil is a silver-based conductive paste.

[0054] Step 3) Install the chip. One end of the chip is connected to the starting section of the coil. A hole is punched on the substrate at the other end of the chip and the end of the coil circuit. At the hole position, a circuit is printed from the back of the substrate to connect the other end of the chip and the end of the coil circuit to form a closed loop, and a flexible NFC device is obtained.

[0055] Example 4

[0056] Preparation of flexible near field communication (NFC) devices:

[0057] Step 1) 12g cotton or waste cotton, 40ml 1wt% 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) aqueous solution and 40ml 10wt% NaBr aqueous solution are dispersed in 700ml deionized water using a stirrer. 200g NaClO is slowly added to the mixed solution. During this process, NaOH is used to adjust the pH value of the solution to a value between 9 and 11. After the reaction is completed, the obtained nano-sized cotton or waste cotton fibers are filtered to form a flexible film.

[0058] Step 2) Print a conductive coil on a flexible film. The number of coils, the line width of the coil, the spacing between adjacent coils, and the thickness of the coil are 13, 0.5 mm, 0.3 mm, and 70 μm, respectively. The dimensions of the outermost coil are 40 mm long and 24 mm wide. The material used to print the coil is a silver-based conductive paste.

[0059] Step 3) Install the chip. One end of the chip is connected to the starting section of the coil. A hole is punched on the substrate at the other end of the chip and the end of the coil circuit. At the hole position, a circuit is printed from the back of the substrate to connect the other end of the chip and the end of the coil circuit to form a closed loop, and a flexible NFC device is obtained.

[0060] Example 5

[0061] Preparation of flexible near field communication (NFC) devices:

[0062] Step 1) 12g cotton or waste cotton cloth, 50ml 1wt% 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) aqueous solution and 60ml 10wt% NaBr aqueous solution are dispersed in 700ml deionized water using a stirrer. 300g NaClO is slowly added to the mixed solution. During this process, NaOH is used to adjust the pH value of the solution to a value between 9 and 11. After the reaction is completed, the obtained nano-sized cotton or waste cotton cloth fibers are filtered to form a flexible film.

[0063] Step 2) Print a conductive coil on a flexible film. The number of coils, the line width of the coil, the spacing between adjacent coils, and the thickness of the coil are 14, 0.4 mm, 0.4 mm, and 70 μm, respectively. The dimensions of the outermost coil are 40 mm long and 24 mm wide. The material used to print the coil is a silver-based conductive paste.

[0064] Step 3) Install the chip. One end of the chip is connected to the starting section of the coil. A hole is punched on the substrate at the other end of the chip and the end of the coil circuit. At the hole position, a circuit is printed from the back of the substrate to connect the other end of the chip and the end of the coil circuit to form a closed loop, and a flexible NFC device is obtained.

[0065] Example 6

[0066] Preparation of flexible near field communication (NFC) devices:

[0067] Step 1) 12g cotton or waste cotton, 30ml 1wt% 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) aqueous solution and 25ml 10wt% NaBr aqueous solution are dispersed in 700ml deionized water using a stirrer. 150g NaClO is slowly added to the mixed solution. During this process, NaOH is used to adjust the pH value of the solution to a value between 9 and 11. After the reaction is completed, the obtained nano-sized cotton or waste cotton fibers are filtered to form a flexible film.

[0068] Step 2) Print a conductive coil on a flexible film, the number of coils, the line width of the coil, the spacing between adjacent coils, and the thickness of the coil are 12, 0.6 mm, 0.2 mm, and 70 μm, respectively. The dimensions of the outermost coil are 40 mm long and 24 mm wide. The material used to print the coil is a silver-based conductive paste.

[0069] Step 3) Install the chip. One end of the chip is connected to the starting section of the coil. A hole is punched on the substrate at the other end of the chip and the end of the coil circuit. At the hole position, a circuit is printed from the back of the substrate to connect the other end of the chip and the end of the coil circuit to form a closed loop, and a flexible NFC device is obtained.

[0070] Example 7

[0071] Preparation of flexible near field communication (NFC) devices:

[0072] Step 1) 12g cotton or waste cotton, 40ml 1wt% 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) aqueous solution and 40ml 10wt% NaBr aqueous solution are dispersed in 700ml deionized water using a stirrer. 200g NaClO is slowly added to the mixed solution. During this process, NaOH is used to adjust the pH value of the solution to a value between 9 and 11. After the reaction is completed, the obtained nano-sized cotton or waste cotton fibers are filtered to form a flexible film.

[0073] Step 2) Print a conductive coil on a flexible film. The number of coils, the line width of the coil, the spacing between adjacent coils, and the thickness of the coil are 13, 0.65 mm, 0.2 mm, and 70 μm, respectively. The dimensions of the outermost coil are 40 mm long and 24 mm wide. The material used to print the coil is a silver-based conductive paste.

[0074] Step 3) Install the chip. One end of the chip is connected to the starting section of the coil. A hole is punched on the substrate at the other end of the chip and the end of the coil circuit. At the hole position, a circuit is printed from the back of the substrate to connect the other end of the chip and the end of the coil circuit to form a closed loop, and a flexible NFC device is obtained.

[0075] Example 8

[0076] Preparation of flexible near field communication (NFC) devices:

[0077] Step 1) 12g cotton or waste cotton cloth, 50ml 1wt% 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) aqueous solution and 60ml 10wt% NaBr aqueous solution are dispersed in 700ml deionized water using a stirrer. 300g NaClO is slowly added to the mixed solution. During this process, NaOH is used to adjust the pH value of the solution to a value between 9 and 11. After the reaction is completed, the obtained nano-sized cotton or waste cotton cloth fibers are filtered to form a flexible film.

[0078] Step 2) Print a conductive coil on a flexible film, the number of coils, the line width of the coil, the spacing between adjacent coils, and the thickness of the coil are: 12, 0.3mm, 0.5mm, 70μm. The dimensions of the outermost coil are: 40mm long and 24mm wide. The material used for printing the coil is a silver-based conductive paste.

[0079] Step 3) Install the chip. One end of the chip is connected to the starting section of the coil. A hole is punched on the substrate at the other end of the chip and the end of the coil circuit. At the hole position, a circuit is printed from the back of the substrate to connect the other end of the chip and the end of the coil circuit to form a closed loop, and a flexible NFC device is obtained.

[0080] Example 9

[0081] Preparation of flexible near field communication (NFC) devices:

[0082] Step 1) 12g cotton or waste cotton, 15ml 1wt% 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) aqueous solution and 15ml 10wt% NaBr aqueous solution are dispersed in 700ml deionized water using a stirrer. 80g NaClO is slowly added to the mixed solution. During this process, NaOH is used to adjust the pH value of the solution to a pH value between 9 and 11. After the reaction is completed, the obtained nano-sized cotton or waste cotton fibers are filtered to form a flexible film.

[0083] Step 2) Print the conductive coil on the flexible film. The number of coils, the line width of the coil, the spacing between adjacent coils, and the thickness of the coil are 11, 0.5 mm, 0.2 mm, and 70 μm, respectively. The dimensions of the outermost coil are 40 mm long and 24 mm wide. The material used for printing the coil is copper-based conductive paste.

[0084] Step 3) Install the chip. One end of the chip is connected to the starting section of the coil. A hole is punched on the substrate at the other end of the chip and the end of the coil circuit. At the hole position, a circuit is printed from the back of the substrate to connect the other end of the chip and the end of the coil circuit to form a closed loop, and a flexible NFC device is obtained.

[0085] Example 10

[0086] Preparation of flexible near field communication (NFC) devices:

[0087] Step 1) 12g cotton or waste cotton cloth, 20ml 1wt% 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) aqueous solution and 20ml 10wt% NaBr aqueous solution are dispersed in 700ml deionized water using a stirrer. 100g NaClO is slowly added to the mixed solution. During this process, NaOH is used to adjust the pH value of the solution to a value between 9 and 11. After the reaction is completed, the obtained nano-sized cotton or waste cotton cloth fibers are filtered to form a flexible film.

[0088] Step 2) Print the conductive coil on the flexible film. The number of coils, the line width of the coil, the spacing between adjacent coils, and the thickness of the coil are 12, 0.5 mm, 0.3 mm, and 70 μm, respectively. The dimensions of the outermost coil are 40 mm long and 24 mm wide. The material used for printing the coil is copper-based conductive paste.

[0089] Step 3) Install the chip. One end of the chip is connected to the starting section of the coil. A hole is punched on the substrate at the other end of the chip and the end of the coil circuit. At the hole position, a circuit is printed from the back of the substrate to connect the other end of the chip and the end of the coil circuit to form a closed loop, and a flexible NFC device is obtained.

[0090] Embodiment 11

[0091] Preparation of flexible near field communication (NFC) devices:

[0092] Step 1) 12g cotton or waste cotton, 40ml 1wt% 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) aqueous solution and 40ml 10wt% NaBr aqueous solution are dispersed in 700ml deionized water using a stirrer. 200g NaClO is slowly added to the mixed solution. During this process, NaOH is used to adjust the pH value of the solution to a value between 9 and 11. After the reaction is completed, the obtained nano-sized cotton or waste cotton fibers are filtered to form a flexible film.

[0093] Step 2) Print the conductive coil on the flexible film. The number of coils, the line width of the coil, the spacing between adjacent coils, and the thickness of the coil are 13, 0.65 mm, 0.2 mm, and 70 μm, respectively. The dimensions of the outermost coil are 40 mm long and 24 mm wide. The material used for printing the coil is copper-based conductive paste.

[0094] Step 3) Install the chip. One end of the chip is connected to the starting section of the coil. A hole is punched on the substrate at the other end of the chip and the end of the coil circuit. At the hole position, a circuit is printed from the back of the substrate to connect the other end of the chip and the end of the coil circuit to form a closed loop, and a flexible NFC device is obtained.

[0095] Example 12

[0096] Preparation of flexible near field communication (NFC) devices:

[0097] Step 1) 12g cotton or waste cotton cloth, 50ml 1wt% 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) aqueous solution and 60ml 10wt% NaBr aqueous solution are dispersed in 700ml deionized water using a stirrer. 300g NaClO is slowly added to the mixed solution. During this process, NaOH is used to adjust the pH value of the solution to a value between 9 and 11. After the reaction is completed, the obtained nano-sized cotton or waste cotton cloth fibers are filtered to form a flexible film.

[0098] Step 2) Print a conductive coil on a flexible film. The number of coils, the line width of the coil, the spacing between adjacent coils, and the thickness of the coil are 14, 0.4 mm, 0.4 mm, and 70 μm, respectively. The dimensions of the outermost coil are 40 mm long and 24 mm wide. The material used to print the coil is a copper-based conductive paste.

[0099] Step 3) Install the chip. One end of the chip is connected to the starting section of the coil. A hole is punched on the substrate at the other end of the chip and the end of the coil circuit. At the hole position, a circuit is printed from the back of the substrate to connect the other end of the chip and the end of the coil circuit to form a closed loop, and a flexible NFC device is obtained.

[0100] As an example, Figure 1 The flexible near field wireless communication (NFC) device prepared according to Example 2 is shown. (a) is the front side of the NFC device; (b) is the back side of the NFC device.

[0101] Embodiment 13

[0102] The NFC device product of the present invention is used for close-range wireless communication with a mobile phone. The specific steps are as follows:

[0103] (1) Use the NFC app on your mobile phone to write instructions into the NFC device product of the present invention;

[0104] (2) When the NFC device product with the command written in step (1) is placed close to the mobile phone, the mobile phone automatically opens the written command content and completes the recognition and transmission of the information;

[0105] As an example, Figure 2 The NFC device that writes URL commands is demonstrated. When it is close to a mobile phone, the mobile phone automatically opens the written URL / webpage.

[0106] Embodiment 14

[0107] The NFC device product of the present invention is used to open the application of the smart door lock. The specific steps are as follows:

[0108] (1) Place the NFC device product of the present invention close to the NFC identification area of ​​the door lock, and use the mobile phone door lock app to complete the verification and adding process;

[0109] (2) When the verified NFC device is brought close to the smart door lock, the door lock is opened.

[0110] As an example, Figure 3 Demonstrated the application of NFC device to open smart door lock.

[0111] Embodiment 15

[0112] The NFC device product of the present invention is integrated on the surface of an object to prepare an application of an intelligent product, and the specific steps are as follows:

[0113] (1) Stick the NFC device on the surface of an object and integrate it with the object (such as a glass, clothes, etc.);

[0114] (2) Use the NFC app on your phone to write commands (such as songs, phone numbers, etc.) into the NFC device.

[0115] (3) When a mobile phone is placed close to the NFC device of the above-mentioned items, the mobile phone automatically executes the written instructions (such as automatically playing the written song, automatically dialing the written phone number, etc.), thus realizing the intelligence of ordinary items;

[0116] Similarly, this NFC device can also be integrated into other items to form an integrated product, which can perform short-range wireless communication with compatible devices to conveniently and quickly execute written instructions.

[0117] As an example, Figure 4 The company demonstrated an NFC device integrated into a glass cup, which automatically plays songs when a phone is brought close to it.

[0118] As an example, Figure 5 The demonstration showed how NFC devices were integrated into clothing, automatically dialing emergency contacts when a mobile phone was close to them. This can be used to quickly contact family members when children or the elderly are lost.

Claims

1. A method for preparing a flexible short-range wireless communication device, characterized in that: The following steps are involved: (1) Converting waste cotton cloth or cotton into nano-sized fibers using an oxidizing agent; (2) assembling the nano-sized fibers obtained in step (1) into a flexible film; (3) Design the number of coils, coil line width, coil thickness, spacing between adjacent coils, and coil length of the flexible short-range wireless communication device NFC; (4) printing a coil circuit on the flexible film obtained in step (2) according to the coil parameters designed in step (3); (5) An NTAG chip is installed on the coil circuit printed in step (4). The terminal end of the coil circuit is connected to the chip by punching a hole in the substrate and printing a circuit from the back of the substrate to form a closed loop, thereby obtaining a flexible short-range wireless communication device NFC.

2. The method for preparing a flexible short-range wireless communication device according to claim 1, characterized in that: In step (1), the oxidizing agent is a combination of 2,2,6,6-tetramethylpyridine-1-oxyl free radical TEMPO, sodium bromide NaBr, and sodium hypochlorite NaClO; and the mass ratio of waste cotton cloth or cotton, TEMPO, NaBr and NaClO is 12: (0.1-0.7): (1.0-7): (50-350).

3. The method for preparing the flexible short-range wireless communication device according to claim 1, characterized in that: In step (3), the number of coil turns, the line width of the coil, the spacing between adjacent coils, and the thickness of the coil of the NFC device are: 11-14, 0.4-0.7 mm, 0.2-0.5 mm, and 70 μm, respectively; the size of the outermost coil is: 40 mm long × 24 mm wide.

4. The method for preparing a flexible short-range wireless communication device according to claim 1, characterized in that: In step (4), the material used to print the coil circuit is silver or copper-based conductive paste.

5. Application of the flexible short-range wireless communication device prepared by the preparation method according to any one of claims 1 to 4 in short-range wireless communication.

6. The use according to claim 5, characterized in that The steps are: writing content or instructions on the chip of the flexible short-range wireless communication device, and when the compatible device is close, short-range wireless communication with the compatible device is realized.

7. The use according to claim 6, characterized in that The compatible devices include but are not limited to: mobile phones and smart door locks.

8. The use according to claim 6, characterized in that Integrate NFC devices that write content or instructions into ordinary commodities to form integrated commodities with short-range wireless communication functions, giving ordinary commodities intelligent attributes.

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