Two-dimensional code subcutaneous microchip and manufacturing method and application thereof

Abstract

The application discloses a two-dimensional code subcutaneous microchip, which comprises a substrate and at least two pattern elements arranged on the substrate, the pattern elements are arranged to be recognizable by an ultrasonic-based imaging device and are converted into black elements and white elements of a corresponding two-dimensional code. The application also provides a manufacturing method of the two-dimensional code subcutaneous microchip, after selecting an ultrasonic-based imaging mode, the material and structure of the microchip are selected according to the imaging mode, the size of each pattern element of the microchip is determined, and finally the microchip is manufactured. The microchip of the application is applied in personal identification and authentication, can be implanted under the skin of a person, and is recognizable by an ultrasonic-based imaging device. The application can be applied in various identity identification and authentication, is convenient to use, and will not be forgotten, misplaced or lost, and compared with biological feature identification based on exposure or physical entity token identification, can provide better privacy and security.

Description

Technical Field

[0001] This invention relates to the field of information recognition, and in particular to a QR code subcutaneous microchip, its manufacturing method, and its application. Background Technology

[0002] Information technology and internet services have made people's lives more convenient; at the same time, the threat of personal information leakage or theft is also increasing. To ensure personal privacy and information security, user identification and authentication (or identity verification) technologies are widely used in various applications, including access, payment or transfer, transit, and personal healthcare. In medical emergencies, it is crucial for healthcare professionals to promptly identify patients' vital medical information (such as blood type, allergies, and amnesia); especially for patients who cannot provide their own medical information, such as those with amnesia or communication impairments (e.g., Alzheimer's disease, vegetative state). Identification and authentication information can generally be carried by three media: text or graphic passwords, biometrics (fingerprints, facial recognition), and physical identification tokens or cards (such as radio frequency identification (RFID)). In recent years, many studies have reported on how to enhance the privacy and security of identification and authentication while maintaining their convenience.

[0003] Passwords are widely used but can be forgotten or stolen, making this method inconvenient and insecure. In contrast, biometric identification and authentication, utilizing each person's unique biometric information, is more convenient because it eliminates the need to remember complex passwords, and related research is increasing. However, biometric identification technology still faces privacy and security issues; this is because the biometric features used are themselves part of user privacy and are difficult to hide or keep secret. For example, facial and even iris information can be recorded in high-resolution images, fingerprints can be collected by touching objects, and voices can be recorded or synthesized. Leaked biometric features can be maliciously used (such as forgery and replay attacks) in identification and authentication systems, ultimately leading to significant losses.

[0004] Besides biometric identification technology, RFID plays a crucial role in identification and authentication. RFID-based contactless smart cards are widely used in many security-critical applications, such as electronic passports, physical access control, and contactless credit card payment systems. Particularly in healthcare systems, RFID bracelets or necklaces worn by patients can reduce the risk of misidentification and improve patient management. However, RFID bracelets or necklaces can be forgotten or lost. In 2004, the first implantable RFID chip, called VeriChip, was approved by the U.S. Food and Drug Administration (FDA) for patient identification. Both non-implantable and implantable RFID are useful in various identification and authentication applications, with implantable RFID being more convenient because it is automatically carried by the user and can be considered a biometric "prosthetic." However, from a security perspective, both non-implantable and implantable RFID chips still face security threats because RFID tags can be read wirelessly and quickly without the individual's knowledge or consent. Specifically, regardless of whether the RFID is implantable, spoofing attacks can be launched by scanning the RFID tag or by eavesdropping on the data exchange between the RFID tag and the reader.

[0005] A Quick Response (QR) code (or two-dimensional barcode) is a two-dimensional barcode that can carry various information and is increasingly used in daily life. Typically, a QR code uses black and white squares (or pixels) as elements, corresponding to the numerical information "0" and "1" respectively. Based on established encoding and decoding rules, it can be easily recognized and utilized by computing systems. The information can then be further processed automatically and efficiently, including information storage, comparison with information in databases, and linking to web pages. Therefore, QR codes are widely used in various applications: not only in inventory tracking and product marketing, but also in personal identification and authentication, such as QR code-based access control systems or using QR codes (such as those printed on paper cards) as identity verification. In particular, QR code identity tags have been used for healthcare purposes; for example, bracelets or necklaces using QR code identification have been used for outpatient identification and emergency medical services.

[0006] Therefore, those skilled in the art are dedicated to developing a QR code subcutaneous microchip, its manufacturing method, and its applications. This chip is convenient to use in various identity recognition and authentication applications, and will not be forgotten, misplaced, or lost. It can be used at any time for medical identification, access control, and payment or bank transfer. In addition to its convenience, it can provide better privacy and security compared to biometric identification or physical token identification (such as necklaces or bracelets) based on exposed biometrics. Summary of the Invention

[0007] To achieve the above objectives, the present invention provides a QR code subcutaneous microchip, comprising:

[0008] Base;

[0009] At least two pattern elements are set on the base;

[0010] The pattern elements are configured to be recognizable by an ultrasound-based imaging device and converted into black and white elements of a corresponding QR code.

[0011] Furthermore, the substrate is made of silicon, and the pattern elements include aperture elements and planar elements, which are configured to be recognizable by an ultrasonic microscopy device.

[0012] Furthermore, the substrate is made of silicon dioxide, and the pattern elements include a first pattern element coated with a coating and a second pattern element uncoated, wherein the first pattern element and the second pattern element have different light absorption efficiencies (i.e. different light absorption intensities), and the first pattern element and the second pattern element are configured to be recognizable by an acoustic resolution photoacoustic microscopy device.

[0013] The present invention also provides a method for manufacturing the QR code subcutaneous microchip as described above, comprising the following steps:

[0014] Choose an ultrasound-based imaging method;

[0015] The material and structure of the microchip are selected according to the imaging method;

[0016] Determine the size of each pattern element of the microchip;

[0017] The microchip is manufactured according to the stated dimensions.

[0018] Furthermore, the ultrasound-based imaging methods include ultrasound microscopy and acoustic resolution photoacoustic microscopy.

[0019] Furthermore, when the ultrasound-based imaging method is the ultrasound microscopy imaging method, the substrate of the microchip is silicon, and the pattern elements on the substrate include hole elements and planar elements.

[0020] Furthermore, the steps for manufacturing the microchip include:

[0021] Photolithography is performed using photoresist on a silicon substrate;

[0022] The silicon substrate is etched using a deep silicon etching system with inductively coupled plasma;

[0023] The photoresist was removed by ultrasonic cleaning.

[0024] Polydimethylsiloxane is spin-coated onto the silicon substrate for protection.

[0025] Furthermore, when the ultrasound-based imaging method is the acoustic resolution photoacoustic microscopy imaging method, the substrate of the microchip is silicon dioxide, and the pattern elements on the substrate include a first pattern element with a coating and a second pattern element without a coating, wherein the first pattern element and the second pattern element have different light absorption efficiencies (i.e. different light absorption intensities).

[0026] Furthermore, the steps for manufacturing the microchip include:

[0027] Photolithography is performed using photoresist on a silicon dioxide substrate;

[0028] Titanium is deposited using magnetron sputtering to form the first pattern element and the second pattern element;

[0029] Ultrasonic cleaning is used to remove the photoresist.

[0030] Polydimethylsiloxane is spin-coated onto the silicon dioxide substrate for protection.

[0031] This invention also provides an application of the QR code subcutaneous microchip as described above in personal identification and authentication, including:

[0032] Generate a corresponding QR code based on the information to be identified;

[0033] The QR code is used to manufacture the QR code subcutaneous microchip;

[0034] The QR code subcutaneous microchip is implanted under the skin of an individual;

[0035] The pattern elements of the QR code subcutaneous microchip are identified using an ultrasound-based imaging device and converted into corresponding QR code information.

[0036] The present invention has the following technical effects:

[0037] 1. This invention addresses the privacy and security issues of exposed biometric features, as well as the convenience and security problems of traditional personal identification and authentication methods. This invention proposes a QR code subcutaneous microchip (QRC-SM) technology, in which the microchip is implanted subcutaneously for personal identification and authentication. Therefore, because it is hidden under the skin, this method can solve the aforementioned privacy and security issues; furthermore, because it is embedded in the human body, there are no problems of theft, loss, or forgetting.

[0038] 2. This invention solves the security problem of RFID. Implantable RFID can be read wirelessly and non-contactly, but this is susceptible to eavesdropping and spoofing attacks. This invention uses ultrasound-related imaging techniques, including ultrasound microscopy and acoustic resolution photoacoustic microscopy, which require contact with a coupling medium during reading, thus avoiding eavesdropping and spoofing attacks.

[0039] The above can be summarized as convenience, privacy, and security.

[0040] Convenience: QRC-SM is easy to use in various identity recognition and authentication applications. It is not forgotten, misplaced, or lost, so it can be used for medical identification, access control, and payment or bank transfer at any time.

[0041] Privacy and security: In addition to convenience, QRC-SM offers better privacy and security compared to biometric identification or physical token identification (such as necklaces or bracelets) that are exposed to the outside, because personal information is hidden under the skin and cannot be disclosed.

[0042] 3. The main materials used in QRC-SM in this invention are silicon (Si), titanium (Ti), silicon dioxide (SiO2) and dimethylsiloxane PDMS, all of which are biocompatible and can ensure human safety.

[0043] 4. The imaging methods in this invention, namely ultrasonic microscopy and acoustic resolution photoacoustic microscopy, do not emit ionizing radiation and can be considered safe for the human body.

[0044] 5. Si, Ti, and SiO2 are all compatible with standard semiconductor device manufacturing technologies. Therefore, QRC-SM holds promise for large-scale manufacturing.

[0045] 6. The QRC-SM feature size is 100μm (elements are "hole" and "plane") and 150μm (elements are "titanium coated" and "uncoated"). Since this size is not very precise, it may allow the use of low-cost manufacturing technologies, such as photolithography and 3D printing (additive manufacturing).

[0046] 7. The most advanced ultrasonic microscopy and acoustic resolution photoacoustic microscopy systems can achieve real-time imaging. Therefore, the present invention proposes to use ultrasonic microscopy and acoustic resolution photoacoustic microscopy to read QRC-SM, which can achieve fast reading and meet the reading speed requirements of practical applications.

[0047] 8. Personal information placed under the skin and encoded into a QR code can be automatically and efficiently identified and authenticated by machines.

[0048] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0049] Figure 1 is a schematic diagram illustrating the working principle of a preferred embodiment of the QR code subcutaneous microchip (QRC-SM) of the present invention, wherein... Figure 1A This describes the working principle of ultrasound microscopy (USM). Figure 1B This is the working principle of acoustic-resolution photoacoustic microscopy (AR-PAM).

[0050] Figure 2 This section presents the design, fabrication, and preliminary characterization of QRC-SMs; (A) a traditional QRC with "black" and "white" surfaces; (BD) a QRC-SM with "holes" and "planar surfaces" for use with a USM; (EG) a QRC-SM with "titanium coating" and "uncoated" surfaces for use with an AR-PAM; (H) the depth resolution capability of the USM; (I) the lateral resolution of the USM; (J) the lateral resolution of the AR-PAM; (K,L) images of QRC-SMs, with the left side showing QRC-SMs with "titanium coating" and "uncoated" surfaces, and the right side showing QRC-SMs with "holes" and "planar surfaces."

[0051] Figure 3 This is a schematic diagram of a QR code according to a preferred embodiment of the present invention;

[0052] Figure 4 This is a schematic diagram of the manufacturing process of QRC-SM;

[0053] Figure 5 Here are schematic diagrams of ex vivo imaging of QRC-SM with "pore" and "plane" elements; (A) 3D structural diagram of QRC-SM with "pore" and "plane" elements, and depth map measured by profilometry; (B) USM imaging results of uncovered QRC-SM; (C) B-mode image corresponding to the dashed line in Figure B; (D) USM imaging results of QRC-SM covered with 2.3 mm thick chicken breast tissue; Scale bar: 500 μm;

[0054] Figure 6This is a schematic diagram of a live-cell QRC-SM with "hole" and "plane" elements; (A) Photograph showing the process of implanting QRC-SM into nude mice; (B) 3D schematic diagram of QRC-SM implantation under the skin of mice; (C) Nude mice after QRC-SM implantation; (D) USM imaging results of implanted QRC-SM; (E) Workflow of the CVQR algorithm; (F) Depth-encoded image as input; (G) Output after CNN-based detection and super-resolution processing; (H) Output after binarization; (I) Final output; Scale bar: 500μm;

[0055] Figure 7 These are schematic diagrams of ex vivo imaging of QRC-SM with "titanium coating" and "uncoated" elements; (A) AR-PAM imaging results of uncoated QRC-SM; (B) Mode B image corresponding to the dashed line in Figure A; (C) AR-PAM imaging results of QRC-SM covered by 2.3 mm thick chicken breast tissue; Scale bar: 500 μm;

[0056] Figure 8 These are in vivo experimental illustrations of QRC-SM with and without "titanium coating" elements; (A) Photograph showing the process of implanting QRC-SM into nude mice; (B) 3D schematic diagram of QRC-SM implantation under the skin of mice; (C) Nude mice with implanted QRC-SM; (D) AR-PAM imaging results of implanted QRC-SM; (E) Workflow of the CVQR algorithm; (F) MAP image as input; (G) Output after CNN-based detection and super-resolution processing; (H) Output after binarization; (I) Final output; (J) AR-PAM imaging results of implanted QRC-SM using a 670nm laser wavelength; (K) Vascular enhancement image based on Figure J. Scale bar: 500μm (applicable to D, J, and K). Detailed Implementation

[0057] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0058] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0059] As shown in Figure 1, this invention provides a QR code subcutaneous microchip (QRC-SM) 3, designed to enhance privacy and security while maintaining ease of access. The QRC-SM under the skin can carry useful and private information. The QR code subcutaneous microchip 3 provided by this invention includes a substrate and at least two identifiable pattern elements disposed on the substrate. By selecting an appropriate imaging method, the corresponding pattern elements can be identified, thereby converting the identified pattern elements into black and white elements corresponding to the QR code, in order to read the corresponding information.

[0060] Since the QRC-SM provided by this invention is implanted under the user's skin 1 (located between the user's skin 1 and tissue 2) during use, a suitable imaging method is needed to read the QR code image under the skin in order to recognize the QR code on the QRC-SM. Pure optical imaging technology has limited penetration depth in human tissue, approximately 1 mm, making it unsuitable for subcutaneous imaging. Ultrasound-related imaging technology has a high penetration depth in tissue and is suitable for subcutaneous imaging. Therefore, this invention selects two imaging methods: ultrasound imaging and photoacoustic imaging, such as ultrasound microscopy (USM) and acoustic-resolution photoacoustic microscopy (AR-PAM), where AR-PAM is a method of photoacoustic imaging. Furthermore, the QRC-SM chip size should be as small as possible to minimize the impact on tissue during implantation and facilitate QRC-SM implantation. Therefore, this invention selects microscopic imaging methods, such as USM and AR-PAM.

[0061] USM and AR-PAM can provide sufficient penetration depth and spatial resolution. Corresponding to these two imaging methods, this invention proposes two corresponding types of QRC-SM. For example... Figure 1A As shown, because the ultrasonic waves emitted by the ultrasonic probe 41 are highly sensitive to the depth of the reflecting surface, this invention designs and manufactures the QRC-SM using "holes" and "planes" (with different depths) on the substrate to represent the "black" and "white" elements in a traditional QR code. The USM utilizes the difference in the time (i.e., time of flight) of receiving the reflected ultrasonic signals to reconstruct the original QR code image. Figure 1BAs shown, since photoacoustic imaging is highly sensitive to light absorption, this invention also designs and manufactures the QRC-SM using a first pattern element (coated, such as a "titanium coating") (strong light absorption) and a second pattern element (uncoated, i.e., "non-coated" element) (weak light absorption) on the substrate. That is, the first and second pattern elements have different light absorption efficiencies (i.e., different light absorption intensities), thus representing the "black" and "white" elements in a traditional QR code. Utilizing different photoacoustic signal intensities, the original QR code image is reconstructed via AR-PAM. As described below, this invention demonstrates in vitro or in vivo imaging. Compared to existing personal identification and authentication technologies, implantable QRC-SM promises to achieve privacy, security, and convenient personal identification and authentication functions. For AR-PAM, this invention selects a 1064nm near-infrared wavelength pulsed laser for photoacoustic excitation within the biological window (laser is conducted through fiber optic cable 42) to ensure sufficient penetration. Neither USM nor AR-PAM emits ionizing radiation and can be considered safe for the human body. The most advanced USM and AR-PAM systems currently available can achieve real-time imaging. Therefore, this application proposes using USM and AR-PAM to read QRC-SM, which can achieve fast reading and meet the reading speed requirements of practical applications.

[0062] It should be understood that, in addition to USM and AR-PAM, other ultrasound-based imaging systems can also be used, such as medical handheld linear ultrasound probe imaging systems and photoacoustic tomography (PACT) imaging systems. This alternative is a technical solution familiar to those skilled in the art and should be within the scope of protection of this invention. Depending on the imaging method, the pattern elements set on the substrate are arranged according to the types that can be identified by the imaging method.

[0063] It should also be understood that the ultrasonic imaging method of this invention demonstrates the use of the time-of-flight difference of the back-facing ultrasonic signals of "hole" and "plane" elements to distinguish between "black" and "white" elements in a QR code; in addition to the above mechanism, other mechanisms, such as ultrasonic signal amplitude, can also be used. Similarly, the photoacoustic imaging method of this invention demonstrates the use of the photoacoustic signal amplitude difference between a first pattern element (coated, such as a "titanium coating") and a second pattern element (uncoated, i.e., an "uncoated" element); in addition to the above mechanism, other mechanisms can also be used, such as different excitation wavelengths generating different photoacoustic signal amplitudes. This alternative is a technical solution familiar to those skilled in the art and should be within the scope of protection of this invention. Furthermore, the photoacoustic imaging method demonstrates the use of 1064 nm. In fact, other wavelengths are also possible as long as the required penetration depth can be achieved. Therefore, selecting different excitation wavelengths and combining them with different photoacoustic systems (such as the PACT described above) should be within the scope of protection of this invention.

[0064] To achieve a QRC-SM that allows for ultrasonic imaging, this invention selects a silicon wafer (the substrate is chosen as silicon) that can provide a hard reflective surface. Elements recognizable by the ultrasonic imaging method are then designed on the silicon wafer, with different elements representing the "black" and "white" elements in the QR code. For example, when using USM imaging, a QRC-SM with "hole" and "plane" elements is designed on the silicon wafer. The back-facing ultrasonic signals of the "hole" and "plane" elements have a time-of-flight difference, which can be used to acquire the "black" and "white" elements in the QR code. When using AR-PAM imaging, to achieve a QRC-SM sensitive to light absorption to allow photoacoustic imaging, this invention selects to coat a 100nm titanium layer (patterned using photolithography) on a silicon dioxide substrate (the substrate is silicon dioxide). Titanium is chosen because its light absorption at a wavelength of 1064nm is much stronger than that of silicon dioxide, thus generating a stronger photoacoustic signal. Thus, elements with "titanium coating" and "uncoated" have different photoacoustic signal amplitudes, which can be used to acquire the "black" and "white" elements in the QR code.

[0065] For QRC-SM with "pore" and "plane" elements, the size of each element is designed according to the resolution of the USM system. The lateral resolution of the USM system can be 52 μm. Therefore, this invention designs the length of each "pore" and "plane" element to be 100 μm, making it sufficient for the USM system to resolve adjacent elements in the image. Furthermore, by using the time at the peak of the ultrasound A-line signal envelope and considering the velocity of sound in biological tissue, the depth resolution of the USM system is approximately or less than 10 μm. Therefore, this invention designs the depth of each "pore" element to be 30 μm.

[0066] Similarly, for the QRC-SM with "titanium coated" and "uncoated" elements, the size of each element is designed according to the resolution of the AR-PAM system. The lateral resolution of the AR-PAM system can be 65 μm. Therefore, the present invention designs the length of each "titanium coated" and "uncoated" element to be 150 μm.

[0067] This invention provides a method for manufacturing a QR code subcutaneous microchip 3, comprising the following steps:

[0068] Step 1: Select Imaging Method. Based on the above description, either USM or AR-PAM can be selected. It should be understood that before Step 1, the QR code subcutaneous microchip of this invention can design a corresponding QR code based on the key information required for identification and authentication, and then manufacture a QRC-SM containing that key information according to the selected imaging method.

[0069] Step 2: Select the materials and structure of the QRC-SM according to the imaging method. For example, ... Figure 2 As shown, based on the USM imaging method, silicon wafers can be selected as the substrate material for QRC-SM. Then, "holes" and "planes" are designed on the silicon wafer, corresponding to the "black" and "white" elements of the QR code, respectively. Figure 2 (As shown in A). Figure 2 B-2D display of the relevant QRC-SM schematic diagram. The time-of-flight difference between the back-facing ultrasonic signals of the "hole" and "plane" elements can be used to acquire the "black" and "white" elements in the QR code. For example... Figure 2 As shown in E-2G, titanium can be coated onto a silicon wafer according to the AR-PAM imaging method. Titanium was chosen because its light absorption at a wavelength of 1064nm is much stronger than that of silicon dioxide, thus generating a stronger photoacoustic signal. Therefore, elements with "titanium coating" and "uncoated" have different photoacoustic signal amplitudes, which can be used to acquire the "black" and "white" elements in a QR code.

[0070] Step 3: Determine the size of each element in the QRC-SM so that each element can be resolved under the corresponding microscopic imaging system. Specifically, the size of each element can be determined based on the resolution of the microscopic imaging system. Figure 2 H indicates the depth resolution capability of the USM. For example, for a QRC-SM with "hole" and "plane" elements, the size of each element is designed according to the resolution of the USM system. In some implementations, the lateral resolution of the USM system can be 52 μm ( Figure 2I). Therefore, the present invention designs the length of each "hole" and "plane" element to be 100 μm, making the USM system sufficient to resolve adjacent elements in an image. Furthermore, by using the time at the peak of the ultrasound A-line signal envelope and considering the speed of sound in biological tissue, the depth resolution of the USM system is approximately or less than 10 μm. Figure 2 H). Therefore, the depth of each "hole" element is designed to be 30 μm in this invention. Figure 2 D). Similarly, for QRC-SMs with "titanium coated" and "uncoated" elements, the size of each element is designed according to the resolution of the AR-PAM system. The lateral resolution of the AR-PAM system can be 65 μm ( Figure 2 J). Therefore, the present invention designs the length of each "titanium coated" and "uncoated" element to be 150 μm (J). Figure 2 G).

[0071] Step 4: Manufacture the QRC-SM chip according to the parameters determined in Step 3. For QRC-SMs with "hole" and "plane" elements, such as... Figure 4 As shown in AD, its manufacturing process is as follows:

[0072] A: Photolithography was performed using SU-8 photoresist on a 500μm silicon substrate.

[0073] B: A deep silicon etching system using inductively coupled plasma is used to etch silicon substrates.

[0074] C: Use ultrasonic cleaning to strip the photoresist.

[0075] D: Spin-coat polydimethylsiloxane (PDMS) (5μm thick) onto the silicon substrate for protection.

[0076] For QRC-SMs with "titanium coating" and "uncoated" elements, such as Figure 4 As shown in EH, its manufacturing process is as follows:

[0077] E: Photolithography was performed using SU-8 photoresist on a 500μm silicon dioxide substrate.

[0078] F: Using magnetron sputtering (Denton multi-target magnetron sputtering system), 100nm titanium is deposited to form a titanium coating, and the areas without titanium coating are left uncoated.

[0079] G: Use ultrasonic cleaning to remove the photoresist.

[0080] H: PDMS (5μm thick) is spin-coated onto a silicon dioxide substrate for protection.

[0081] It should be understood that the fabrication method of QRC-SM is not limited to photolithography. For example, electron beam lithography can be used to fabricate higher resolution QRC-SM, or additive manufacturing (3D printing) can be used to fabricate low-cost QRC-SM. The use of different methods to fabricate QRC-SM should be within the scope of protection of this invention.

[0082] exist Figure 4 D and Figure 4 In H, liquid PDMS (Sylgard 184, Dow Corning) with a weight ratio of 10:1 was used.

[0083] Figure 2 K and 2L show the fabricated QRC-SMs, namely 3mm*3mm (QRC-SM with "holes" and "planes") and 4.3mm*4.3mm (QRC-SM with "titanium coating" and "uncoated" elements), meaning the substrate can be square. It should be understood that the substrate can also be other shapes. The QRC-SM chip is approximately 500μm thick. Figure 2 L).

[0084] The main materials used in the QRC-SM of this invention are Si, Ti, SiO2, and PDMS, all of which are biocompatible and ensure human safety. Furthermore, Si, Ti, and SiO2 are compatible with standard semiconductor device manufacturing technologies. Therefore, QRC-SM can be used for large-scale manufacturing. PDMS is used to protect the surface of QRC-SM and ensure its biocompatibility. Other biocompatible materials that are not easily corroded in vivo can also be used as a protective layer on the surface of QRC-SM. This alternative is a technical solution familiar to those skilled in the art and should be within the scope of protection of this invention.

[0085] Furthermore, the QRC-SM feature sizes are 100μm (elements for “holes” and “planes”) and 150μm (elements for “titanium coating” and “uncoated”). Since these dimensions are not very precise, they may allow for fabrication using low-cost manufacturing techniques, such as photolithography and 3D printing (additive manufacturing).

[0086] It should be understood that QRC-SM can also be fabricated on a flexible substrate to ensure conformal contact with human tissue.

[0087] It should be understood that similar effects can be achieved by modifying the substrate material, coating material, etc., of the two QRC-SMs. For example, the dimerized silicon substrate can be replaced with a flexible substrate, and the titanium coating can be replaced with other metal or non-metal coatings. This alternative solution is a technical solution familiar to those skilled in the art and should be within the scope of protection of this invention.

[0088] Example:

[0089] To demonstrate the application of the QRC-SM of this invention in personal identification and authentication, this invention encodes four representative pieces of information into four QR codes, each QR code representing key information used for specific identification and authentication. The first representative QR code pattern is the encoding of "Eric Li:Type B,Asthma" (…). Figure 3 A) describes the virtual person's name, blood type, and medical records; it can be used for effective and timely medical identification in medical emergencies, allowing healthcare professionals to quickly retrieve important medical information from outpatients and emergency patients. The second representative QR code pattern is the code "Eric Li:CHASE,123456789" (…). Figure 3 B) describes virtual bank account information including username, bank name, and account number; it can be used for identification and authentication during payment or bank transfer processes, thereby ensuring personal account security and asset safety. The third representative QR code pattern is the code "Eric Li: Engineer of Google, 035" (…). Figure 3 C) describes a virtual employee named Eric Li, his employer and position, and his employee number; it can be used for access control in some high-security institutions (such as companies and government agencies), and in addition to physical access control, it can also be used for access control of online services. The fourth representative QR code pattern is the encoding of "https: / / www.ji.sjtu.edu.cn" ( Figure 3 D), which describes the website link of the Joint Institute of Shanghai Jiao Tong University and the University of Michigan; it shows that QRC-SM can be used to link to personal websites to obtain more identity or other information, and also demonstrates that although the capacity of the QR code itself is limited, a larger amount of information can be stored through this linking method.

[0090] based on Figure 3 The invention uses photolithography to create a photomask for manufacturing QRC-SM, which has four patterns.

[0091] The QR code subcutaneous microchip of the present invention is applied in personal identification and authentication, including the following steps:

[0092] Generate the corresponding QR code based on the required key information;

[0093] After selecting the imaging method, the QR code subcutaneous microchip is manufactured according to the above manufacturing method;

[0094] A QR code subcutaneous microchip is implanted under the user's skin;

[0095] The corresponding ultrasound-based imaging device is used to identify the subcutaneous microchip of the QR code and convert it into the corresponding QR code information.

[0096] Imaging effect demonstration:

[0097] I. QRC-SM with "hole" and "plane" elements, and its imaging and QR code reading using USM.

[0098] Figure 5 A represents the QRC-SM manufactured using a profilometer scan. During imaging, the USM's scanning step size in the X and Y directions is 20 μm. After imaging, the open-source artificial intelligence (AI) algorithm released by the WeChat computer vision team is applied to QR code detection and recognition; this algorithm is referred to as "CVQR".

[0099] This invention first attempts imaging on a QRC-SM that does not cover any tissue. In this demonstration, the invention uses… Figure 3 The QR code for C is an example. Figure 5 B represents the obtained depth-coded image. The CVQR algorithm successfully reads "Eric Li: Engineer of Google, 035". Figure 5 C displays the following: Figure 5 B-mode image along the dashed line in B.

[0100] Next, this invention attempts to image a 2.3 mm thick layer of chicken breast tissue covering the QRC-SM, making the QRC-SM invisible to the naked eye beneath the chicken breast. Using... Figure 3 The QR code in section C is used as an example. Additionally, tests were conducted on a scanning direction that was not parallel to the boundaries of the QRC-SM (approximately 45 degrees). The scanning results are as follows. Figure 5 As shown in D, the CVQR algorithm can successfully read "Eric Li: Engineer of Google, 035".

[0101] Furthermore, this invention attempts to perform in vivo imaging of QRC-SM implanted in mice. An 8-week-old adult nude mouse was used; a small incision was first made in its skin (…). Figure 6 A and 6B), then, QRC-SM (with "hole" and "plane" elements) Figure 3 The QR code pattern was implanted under the mouse's skin. After implantation, the QR code pattern was covered and hidden by the mouse's skin, making it invisible. Figure 6 C). Scan results as follows Figure 6 As shown in D, the CVQR algorithm can successfully read "Eric Li: Engineer of Google, 035". Figure 6 E-6I is used Figure 6 Using D as input, demonstrate and illustrate the workflow of CVQR.

[0102] II. The QRC-SM with "titanium coating" and "uncoated" elements, and its imaging and QR code reading using AR-PAM.

[0103] This invention also performs imaging and QR code reading on QRC-SMs with "titanium coating" and "uncoated" elements. Using... Figure 3 A QR code is used as an example. During imaging, the AR-PAM scan step size in the X and Y directions is 30 μm. First, imaging was attempted on the QRC-SM without any tissue coverage; the results are as follows... Figure 7 As shown in Figure A, the CVQR algorithm can successfully read "Eric Li:Type B,Asthma". Figure 7 B shows Figure 7 Image of pattern B along the dashed line in A.

[0104] Next, this invention attempted imaging of a 2.3 mm thick layer of chicken breast tissue covering the QRC-SM. The scanning direction was not parallel to the boundary of the QRC-SM (approximately 45 degrees). The results are as follows. Figure 7 As shown in C. The CVQR algorithm can successfully read "Eric Li:Type B,Asthma".

[0105] Furthermore, this invention attempts to implant QRC-SM into mice for in vivo imaging. QRC-SM with "titanium coating" and "uncoated" elements (…) Figure 3 Pattern A was implanted under the skin of 8-week-old adult nude mice. Figure 8 A-8C). The results are as follows: Figure 8 As shown in D. The CVQR algorithm can successfully read "Eric Li:Type B,Asthma". Figure 8 E-8I is used Figure 8 Using D as input, demonstrate and illustrate the workflow of CVQR.

[0106] Figure 8 J displays a photoacoustic image at an excitation wavelength of 670 nm, showing vascular images other than the QR code. This is because hemoglobin has strong light absorption at 670 nm. To more clearly illustrate the blood vessels, this invention will... Figure 8 The amplitude of the area outside the QR code pattern in J was increased by two times, such as Figure 8 As shown in K, the blood vessels can be seen more clearly.

[0107] To verify the long-term stability and functionality of QRC-SM, we tested QRC-SM with "pore" and "planar" elements, as well as QRC-SM with "titanium coating" and "uncoated" elements, by immersing them in solution. Specifically, the QRC-SM were immersed in phosphate-buffered saline (PBS) solution at 80°C for one month, and then these QRC-SM were imaged by USM and AR-PAM, respectively. This invention confirms the long-term stability of QRC-SM, demonstrating that information can still be read after long-term implantation.

[0108] This invention addresses the privacy and security issues of exposed biometrics, as well as the convenience and security problems of traditional personal identification and authentication methods. In this invention, a QR code subcutaneous microchip (QRC-SM) technology is proposed, in which the microchip is implanted under the skin for personal identification and authentication. Therefore, because it is hidden under the skin, this invention solves the aforementioned privacy and security problems; furthermore, because it is embedded in the human body, there are no issues of theft, loss, or forgetting.

[0109] This invention solves the security problem of RFID. Implantable RFID can be read wirelessly and non-contactly, but this is susceptible to eavesdropping and spoofing attacks. This invention uses ultrasound-related imaging technologies, such as USM and AR-PAM, which require contact with a coupling medium during reading, thus avoiding eavesdropping and spoofing attacks.

[0110] The above can be summarized as convenience, privacy, and security.

[0111] Convenience: QRC-SM is easy to use in various identity recognition and authentication applications. It is not forgotten, misplaced, or lost, so it can be used at any time for medical identification, access control, payment or bank transfer, and other scenarios that require identity recognition and authentication.

[0112] Privacy and security: In addition to convenience, QRC-SM offers better privacy and security compared to biometric identification or physical token identification (such as necklaces or bracelets) that are exposed to the outside, because personal information is hidden under the skin and cannot be disclosed.

[0113] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A QR code subcutaneous microchip, characterized in that, The QR code subcutaneous microchip uses biocompatible materials, including: Base; At least two pattern elements are set on the base; The pattern elements are configured to be recognizable by devices based on ultrasonic microscopy or acoustic resolution photoacoustic microscopy, and converted into black and white elements of the corresponding QR code. The pattern elements include a first pattern element coated with a titanium coating and a second pattern element without a coating. The first and second pattern elements have different light absorption efficiencies, i.e., different light absorption intensities. The first and second pattern elements are configured to be recognizable by an acoustic resolution photoacoustic microscopy device. The size of each pattern element is designed according to the resolution of the photoacoustic microscopy device. The difference in photoacoustic signal amplitude between the first and second pattern elements is used to distinguish between black and white elements in the QR code. Alternatively, the pattern elements include aperture elements and planar elements, configured to be recognizable by an ultrasonic microscopy device. The size of each pattern element is designed according to the resolution of the ultrasonic microscopy device. The difference in the flight time of the back-facing ultrasonic signals of the aperture elements and the planar elements is used to distinguish between black and white elements in the QR code. The substrate is made of silicon or silicon dioxide, and polydimethylsiloxane is spin-coated onto the substrate and the pattern elements; The QR code subcutaneous microchip is configured to be implanted under the skin of the human body for personal identification and authentication; The manufacturing method of the QR code subcutaneous microchip includes: Choose an ultrasound-based imaging method, including ultrasound microscopy and acoustic resolution photoacoustic microscopy. The material and structure of the microchip are selected according to the imaging method; Determine the size of each pattern element of the microchip; The microchip is manufactured according to the stated dimensions.

2. A method for manufacturing a QR code subcutaneous microchip as described in claim 1, characterized in that, Includes the following steps: Choose an ultrasound-based imaging method, including ultrasound microscopy and acoustic resolution photoacoustic microscopy. The material and structure of the microchip are selected according to the imaging method; Determine the size of each pattern element of the microchip; The microchip is manufactured according to the stated dimensions.

3. The manufacturing method as described in claim 2, characterized in that, When the ultrasound-based imaging method is the ultrasound microscopy imaging method, the substrate of the microchip is silicon, and the pattern elements on the substrate include hole elements and planar elements.

4. The manufacturing method as described in claim 3, characterized in that, The steps for manufacturing the microchip include: Photolithography is performed using photoresist on a silicon substrate; The silicon substrate is etched using a deep silicon etching system with inductively coupled plasma; The photoresist was removed by ultrasonic cleaning. Polydimethylsiloxane is spin-coated onto the silicon substrate for protection.

5. The manufacturing method as described in claim 2, characterized in that, When the ultrasound-based imaging method is the acoustic resolution photoacoustic microscopy imaging method, the substrate of the microchip is silicon dioxide, and the pattern elements on the substrate include a first pattern element coated with a titanium coating and a second pattern element without a coating, wherein the first pattern element and the second pattern element have different light absorption efficiencies.

6. The manufacturing method as described in claim 5, characterized in that, The steps for manufacturing the microchip include: Photolithography is performed using photoresist on a silicon dioxide substrate; Titanium is deposited using magnetron sputtering to form the first pattern element and the second pattern element; Ultrasonic cleaning is used to remove the photoresist. Polydimethylsiloxane is spin-coated onto the silicon dioxide substrate for protection.

7. An application of a QR code subcutaneous microchip as described in claim 1 in personal identification and authentication, characterized in that, include: Generate a corresponding QR code based on the information to be identified; The QR code is used to manufacture the QR code subcutaneous microchip; The QR code subcutaneous microchip is implanted under the skin of an individual; The pattern elements of the QR code subcutaneous microchip are identified using an ultrasound-based imaging device and converted into corresponding QR code information.

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