Optical security system based on photoelectric detector and verification and judgment method

Abstract

The invention discloses an optical security system based on a photoelectric detector and a verification and judgment method, and relates to the technical field of photoelectric detection. A laser coding end of the optical security and protection system is used for emitting an optical signal with a specific wavelength and switchable incident intensity, a detection panel of a to-be-identified device comprises a plurality of embedded nanowire photoelectric detectors which are arranged in an array mode, and the embedded nanowire photoelectric detectors are arranged in the mode that when the incident intensity of the optical signal is at different preset intensity levels, the embedded nanowire photoelectric detectors are used for detecting the incident intensity of the optical signal. And when the polarities and / or amplitudes of light current signals of the first loop and the second loop of the embedded nanowire photoelectric detector are different from those of the initial current signals, the signal control module executes an unlocking instruction after judging that quadruple information conforms to preset identification logic. According to the optical security and protection system, multi-dimensional information such as the intensity, polarity, sequence and space path of optical signals is used for combined analysis, and high-safety, high-integration and compact-structure optical coding recognition and security and protection control are achieved.

Description

Technical Field

[0001] This invention relates to the field of photoelectric detection technology, specifically to an optical security system and verification method based on photoelectric detectors. Background Technology

[0002] With the development of photoelectric detection technology, optical security systems that use optical signals for information identification and security authentication are gradually being applied to fields such as safes, access control devices, and smart security terminals. Existing optical identification systems typically emit light signals to the detection device via lasers or light sources, and the photodetector converts the light signals into electrical signals, which are then judged by the control circuit to achieve functions such as unlocking or identity authentication.

[0003] In existing technologies, most optical security systems rely primarily on a single optical parameter for identification, such as detecting whether the light intensity exceeds a preset threshold, identifying a specific wavelength, or determining the position of a single light spot. While these technologies are relatively simple in structure, their security level is limited due to the limited number of identification dimensions, making them susceptible to being cracked by simulating optical signals.

[0004] To enhance security, some existing technologies attempt to achieve more complex optical encryption through multi-parameter combination identification, such as combining information like light intensity, wavelength, time series, or spatial location for joint judgment. However, such systems typically require multiple independent photodetectors, discrete optical components, and complex external signal processing circuits to work together, resulting in complex system structures, large sizes, high power consumption, low system integration and reliability, making it difficult to achieve compact and highly integrated security devices.

[0005] Furthermore, the electrical signal changes generated by traditional photodetectors under different light intensities are relatively simple, usually only showing a linear change in current amplitude, making it difficult to provide multidimensional signal information with obvious distinguishing features. Therefore, in security verification systems based on optical signal sequences or optical coding, their information expression capabilities remain limited.

[0006] Therefore, there is an urgent need to provide an optical security system with high structural integration, capable of multi-dimensional analysis of incident light signals and complex optical coding recognition, so as to improve the security and recognition reliability of the system. Summary of the Invention

[0007] One objective of the first aspect of this invention is to provide an optical security system based on an embedded nanowire photodetector, which solves the technical problems of existing optical security systems that typically rely on a single optical parameter for identification, have limited identification dimensions leading to insufficient security, and require multiple discrete photodetectors and complex external circuits in multi-parameter identification systems, resulting in complex structures and low system integration.

[0008] Another objective of the first aspect of this invention is to further ensure the security and anti-interference capability of the optical coding verification process.

[0009] The second objective of this invention is to provide a verification and judgment method for the aforementioned optical security system.

[0010] According to a first aspect of the present invention, the present invention provides an optical security system based on an embedded nanowire photodetector, comprising: The laser encoding end is used to emit optical signals of a specific wavelength with switchable incident intensity. The device to be identified includes a detection panel for receiving the optical signal. The detection panel includes multiple embedded nanowire photodetectors arranged in an array. Each embedded nanowire photodetector includes a substrate, a first transparent electrode layer, a photosensitive layer, and a second transparent electrode layer stacked sequentially from bottom to top. The photosensitive layer contains multiple periodically arranged nanowire arrays. The first transparent electrode layer and the nanowire arrays form a first circuit, and the second transparent electrode layer and the nanowire arrays form a second circuit. The applied bias voltage of the first transparent electrode layer is greater than the applied bias voltage of the nanowire arrays, so as to generate initial current signals in the first circuit and the second circuit respectively. When the incident intensity of the optical signal is at different preset intensity levels, the polarity and / or amplitude of the photocurrent signals in the first circuit and the second circuit of the embedded nanowire photodetector are different from the initial current signals. The signal control module is used to acquire each current photocurrent signal, and analyze the current incident intensity sequence and current incident path of the laser encoding end according to the magnitude, polarity and amplitude of the current photocurrent signal. When each current photocurrent signal is valid, the current incident intensity sequence matches the preset incident intensity sequence, and the current incident path matches the preset incident path, an unlocking command is generated and sent.

[0011] Optionally, the signal control module is used to determine that the photocurrent signal is valid when the deviation between each current photocurrent signal and its corresponding nominal current value is less than or equal to a preset tolerance threshold.

[0012] Optionally, when the incident intensity is at the first intensity level, the polarity of the photocurrent signal is the same as that of the initial current signal, but the amplitude is reduced. When the incident intensity is at the second intensity level, the polarity of the photocurrent signal is reversed relative to the initial current signal.

[0013] Optionally, the nanowire array is made of silver, with a thickness of any value between 25nm and 35nm and a width of any value between 90nm and 110nm.

[0014] Optionally, the period of the nanowire array is any value between 950nm and 1050nm.

[0015] Optionally, the photosensitive layer is made of indium arsenide and has a thickness of any value between 110nm and 130nm.

[0016] Optionally, both the first transparent electrode layer and the second transparent electrode layer are made of transparent conductive glass, and their thicknesses are any values ​​between 25nm and 35nm.

[0017] Optionally, the thickness of the substrate is any value between 290nm and 310nm.

[0018] According to a second aspect of the present invention, the present invention also provides a verification and judgment method for an optical security system based on an embedded nanowire photodetector as described in any of the preceding claims, comprising the following steps: A preset bias voltage is applied to each embedded nanowire photodetector in the detection panel to generate initial current signals in the first and second circuits, respectively. It receives the optical signal emitted by the laser encoding end and collects the current photocurrent signals generated by the first and second circuits in real time; Determine whether the deviation between each current photocurrent signal and its corresponding nominal current value does not exceed a preset tolerance threshold. If it does not exceed the threshold, the current photocurrent signal is determined to be a valid signal; otherwise, it is determined to be an invalid signal and the verification is terminated. Based on the polarity and amplitude variation of the current photocurrent signal, the corresponding current incident intensity level is identified and recorded in chronological order to form the current incident intensity sequence. Based on the spatial position of the triggered embedded nanowire photodetector, the current incident path sequence is recorded; The current incident intensity sequence and the current incident path sequence are compared with the preset incident intensity sequence and the preset incident path, respectively. When the current photocurrent signal is a valid signal, the current incident intensity level, the current incident intensity sequence, and the incident path sequence all match, an unlock command is output; otherwise, the locked state is maintained.

[0019] Optionally, the step of identifying the corresponding incident intensity level based on the polarity and amplitude variation of the photocurrent signal further includes: The incident intensity level is determined by a joint determination based on the amplitude difference and polarity difference between the photocurrent signals generated by the first circuit and the second circuit, and an illegal input signal is determined when the amplitude difference or polarity relationship does not meet the preset correspondence.

[0020] The optical security system of this invention utilizes an embedded nanowire photodetector to jointly detect the amplitude and polarity of the photocurrent signal generated by the incident light signal. It then combines the incident light intensity sequence and incident path information for multi-dimensional analysis and verification, thereby achieving accurate identification of the optical signal encoding. Compared to existing security methods based on single optical or single electrical signal identification, this invention, by introducing a verification mechanism combining light intensity encoding and spatial path encoding, and determining the validity of the photocurrent signal, effectively suppresses the influence of environmental noise and interference signals on the identification process, improving the system's identification accuracy and stability. Simultaneously, the surface plasmon resonance and local electromagnetic field enhancement effect generated by the nanowire array structure significantly enhances the device's response to incident light signals, enabling different incident light intensities to form distinguishable amplitude and polarity characteristics in the electrical signal, thereby improving the sensitivity and reliability of optical signal encoding identification. Through the aforementioned multi-dimensional encoding and multi-level verification mechanism, a more secure and interference-resistant optical security control system can be achieved.

[0021] Furthermore, in this invention, the signal control module is used to determine that the photocurrent signal is valid when the deviation between each current photocurrent signal and its corresponding nominal current value is less than or equal to a preset tolerance threshold. By comparing the deviation between the current photocurrent signal and the corresponding nominal current value, and determining that the photocurrent signal is valid when the deviation is less than or equal to the preset tolerance threshold, environmental noise, stray light interference, and abnormal signals caused by device current fluctuations can be effectively filtered, thereby improving the accuracy and stability of photocurrent signal determination and further enhancing the reliability of the system's optical signal recognition process.

[0022] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0023] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic structural diagram of an optical security system according to an embodiment of the present invention; Figure 2 This is a schematic incident path diagram of a detection panel according to an embodiment of the present invention; Figure 3 This is a schematic structural diagram of an embedded nanowire photodetector according to an embodiment of the present invention; Figure 4This is a schematic structural diagram of a photosensitive layer and a nanowire array according to an embodiment of the present invention; Figure 5 This is a local light field distribution diagram of a nanowire array according to an embodiment of the present invention under the incident light of a specific wavelength and intensity. Figure 6 This is an absorptivity curve of a photosensitive layer according to an embodiment of the present invention under incident light of a selected wavelength and a specific intensity. Figure 7 This refers to the dark current of the first and second transparent electrode layers under no light irradiation according to an embodiment of the present invention. Figure 8 According to an embodiment of the present invention, the first and second transparent electrode layers are at 1000 W / m 2 1. Photocurrent signal under selected wavelength illumination conditions; Figure 9 According to an embodiment of the present invention, the first and second transparent electrode layers are at 3000 W / m 2 1. Photocurrent signal under selected wavelength illumination conditions; Figure 10 This is a schematic flowchart of a verification and judgment method for an optical security system according to an embodiment of the present invention.

[0024] Figure label: 100-Optical security system, 10-Laser encoding end, 20-Identification device, 21-Detection panel, 22-Embedded nanowire photodetector, 221-Substrate, 222-First transparent electrode layer, 223-Photosensitive layer, 224-Second transparent electrode layer, 225-Nanowire array, 226-First loop, 227-Second loop. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0026] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0027] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0028] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0029] Figure 1 This is a schematic structural diagram of an optical security system according to an embodiment of the present invention. Figure 2 This is a schematic incident path diagram of a detection panel according to an embodiment of the present invention. Figure 3 This is a schematic structural diagram of an embedded nanowire photodetector according to an embodiment of the present invention. Figure 4 This is a schematic structural diagram of a photosensitive layer and a nanowire array according to an embodiment of the present invention. Figure 5 This is a local light field distribution diagram of a nanowire array according to an embodiment of the present invention under incident light of a specific wavelength and intensity. Figure 6 This is an absorptivity curve of the photosensitive layer according to an embodiment of the present invention under incident light of a selected wavelength and specific intensity. Figure 7 This refers to the dark current of the first and second transparent electrode layers under conditions of no light irradiation, according to an embodiment of the present invention. Figure 8 According to an embodiment of the present invention, the first and second transparent electrode layers are at 1000 W / m 2 The photocurrent signal under selected wavelength illumination conditions. Figure 9 According to an embodiment of the present invention, the first and second transparent electrode layers are at 3000 W / m 2 1. Photocurrent signal under selected wavelength light illumination conditions.

[0030] like Figure 1As shown, this invention provides an optical security system 100 based on embedded nanowire photodetectors 22. The optical security system 100 includes a laser encoding end 10, a device to be identified 20, and a signal control module. The laser encoding end 10 is used to emit light signals of a specific wavelength with switchable incident intensity. The device to be identified 20 includes a detection panel 21 for receiving light signals. The detection panel 21 includes multiple embedded nanowire photodetectors 22 arranged in an array. The signal control module is used to collect each photocurrent signal and perform real-time verification and judgment on each photocurrent signal according to a preset verification logic. Here, the number of embedded nanowire photodetectors 22 in the detection panel 21 is nine, and they are distributed in a nine-square grid array. In other embodiments, the array of multiple embedded nanowire photodetectors 22 in the detection panel 21 can also be other matrix arrangements arranged in an array.

[0031] In this embodiment, the laser encoding end 10 is first configured to output laser signals with specific wavelengths and switch between different incident intensities. Specifically, the emission wavelength and incident intensity of the laser signal emitted by the laser encoding end 10 onto the detection panel 21 can be pre-set. This allows for the control of the output amplitude and polarity of the photocurrent signal from the embedded nanowire photodetector 22 in the detection panel 21 by adjusting the laser signal wavelength and incident intensity of the laser encoding end 10. For example, the laser emission wavelength of the laser from the laser encoding end 10 can be any value between 2200nm and 2800nm, and the incident intensity can be 1000W / m². 2 2000W / m 2 Or 3000W / m 2 Alternatively, it could be any other incident intensity that enables the embedded nanowire photodetector 22 to output a photocurrent signal with polarity reversal and amplitude variation.

[0032] like Figure 3 and Figure 4As shown, in this embodiment, the embedded nanowire photodetector 22 includes a substrate 221, a first transparent electrode layer 222, a photosensitive layer 223, and a second transparent electrode layer 224 stacked sequentially from bottom to top. The photosensitive layer 223 has a plurality of periodically arranged nanowire arrays 225 embedded in it. The first transparent electrode layer 222 and the nanowire arrays 225 form a first circuit 226, and the second transparent electrode layer 224 and the nanowire arrays 225 form a second circuit 227. The applied bias voltage of the first transparent electrode layer 222 is greater than the applied bias voltage of the nanowire arrays 225, so that initial current signals are generated in the first circuit 226 and the second circuit 227 respectively. When the incident intensity of the light signal is at different preset intensity levels, the polarity and / or amplitude of the photocurrent signals in the first circuit 226 and the second circuit 227 of the embedded nanowire photodetector 22 are different from the initial current signals. When the light signal sequentially illuminates the corresponding embedded nanowire photodetector 22 in the detection panel 21 according to a preset incident light intensity sequence and a preset incident path, the light signal is guided through the second transparent electrode layer 224 and the photosensitive layer 223 to the nanowire array 225, and generates photocurrent signals with amplitudes and polarities different from the initial current signals in the first circuit 226 and the second circuit 227, respectively. Here, the preset incident light intensity sequence is a light intensity sequence formed by arranging at least two light signals of different incident intensities in a preset order, and the preset incident path is a spatial encoding sequence formed by the light signal acting on different embedded nanowire photodetectors 22 in a preset spatial order.

[0033] In this embodiment, a preset bias voltage is applied to the first transparent electrode layer 222 and the nanowire array 225 of the embedded nanowire photodetector 22 to establish a stable built-in electric field inside the embedded nanowire photodetector 22.

[0034] like Figure 7 As shown, in a specific embodiment, a forward bias voltage of 0.003V is applied to the first transparent electrode layer 222, and a forward bias voltage of 0.002V is applied to the nanowire array 225. This causes an electric field distribution to be formed inside the embedded nanowire photodetector 22, generally from bottom to top and pointing towards the second transparent electrode layer 224. As a result, initial current signals with defined directions are formed in the first circuit 226 and the second circuit 227 respectively under no-light conditions. The initial current signal Ia of the second circuit 227 is -11.8µA, and the initial current signal Ib of the first circuit 226 is 10.5µA.

[0035] When light of a specific wavelength shines on the embedded nanowire photodetector 22, the incident light passes sequentially through the second transparent electrode layer 224 and the photosensitive layer 223 and acts on the metal nanowire array 225 embedded in the photosensitive layer 223, exciting surface plasmon resonances on the structural surface of the nanowire array 225, thereby generating a significant near-field local electromagnetic field enhancement effect around the nanowire array 225 (see reference). Figure 5 The enhanced local light field is absorbed by the photosensitive layer 223 (see reference). Figure 6 This process generates a large number of photogenerated electron-hole pairs within the photosensitive layer 223. Initially, the generated photogenerated carriers are mainly concentrated in the vicinity of the nanowire array 225 and diffuse to the surrounding area driven by the concentration gradient. Simultaneously, under the influence of the built-in electric field within the embedded nanowire photodetector 22, electrons and holes undergo directional separation and transport, with electrons migrating towards higher potential regions and holes migrating in the opposite direction. The generation, diffusion, and directional transport processes of these photogenerated carriers alter the carrier distribution and local electric field distribution within the detector, thereby modulating the currents in the first loop 226 and the second loop 227. That is, as the incident light intensity changes, the number and distribution of photogenerated carriers generated in the photosensitive layer 223 change accordingly, causing changes in both the amplitude and polarity of the output currents in the first loop 226 and the second loop 227, creating a distinguishable difference from the initial current signal under no-light conditions. Therefore, by detecting the amplitude and polarity changes of the output current of the first circuit 226 and the second circuit 227, the incident light intensity information can be converted into identifiable electrical signal characteristics.

[0036] like Figure 8 and Figure 9 As shown, when linearly polarized light in the 2000nm-3000nm band is incident, compared with the current results under no light irradiation, at a current of 1000W / m 2 The photocurrent signal generated under light illumination decreases in value while maintaining the same direction, reaching 3000 W / m. 2 The photocurrent signals generated under light illumination are in opposite directions.

[0037] In a preferred embodiment, polarized light with a wavelength of 2500nm is used for irradiation, at a power of 1000W / m. 2 Under illumination, the photocurrent signal Ia of the second circuit 227 is -3.2µA, and the photocurrent signal Ib of the first circuit 226 is 3.5µA. Compared with no illumination, the directions of Ia and Ib remain unchanged, but their values ​​decrease. At 3000W / m 2 Under light illumination, the photocurrent signal Ia of the second circuit 227 is 14µA, and the photocurrent signal Ib of the first circuit 226 is -10.5µA. Compared with no light illumination, the directions of Ia and Ib change.

[0038] In this embodiment, the signal control module is used to collect each current photocurrent signal, and analyze the current incident intensity sequence and current incident path of the laser encoder based on the magnitude, polarity and amplitude of the current photocurrent signal. When each current photocurrent signal is valid, the current incident intensity sequence matches the preset incident intensity sequence, and the current incident path matches the preset incident path, an unlocking command is generated and sent.

[0039] In one specific embodiment, multiple embedded nanowire photodetectors 22 in the detection panel 21 of the device to be identified 20 are arranged in a nine-square grid array, that is, arranged in a matrix of three rows and three columns. For ease of identification and signal analysis, each embedded nanowire photodetector 22 is numbered (refer to...). Figure 2 ), Figure 2 In (a) of the diagram, the first row is numbered D1, D2, D3 from left to right; the second row is numbered D4, D5, D6 from left to right; and the third row is numbered D7, D8, D9 from left to right. The laser encoding terminal 10 emits a laser signal with a wavelength of 2500nm as the identification light source. The optical security system 100 presets two incident light intensity levels, P1 being 1000W / m². 2 P2 is 3000W / m 2 Different intensities are combined to form an identification coding sequence, i.e., the preset incident light intensity sequence is P2, P1, P2, P1, P1, P2, P1 (refer to...). Figure 2 (a) in the text. The corresponding incident paths are, in sequence, the seven embedded nanowire photodetectors 22 numbered D1, D2, D3, D5, D7, D8, and D9 on the detector panel 21 (refer to...). Figure 2 (b) in the middle.

[0040] After the optical security system 100 is activated, the signal control module applies a preset bias voltage to each embedded nanowire photodetector 22, thereby forming a stable built-in electric field between the first transparent electrode layer 222, the nanowire array 225, and the second transparent electrode layer 224, and generating an initial current signal with a defined direction in the first circuit 226 and the second circuit 227, and the system enters a real-time monitoring state. When the laser encoding end 10 emits an optical signal according to the preset encoding method, the first laser beam with an intensity of P2 first illuminates the embedded nanowire photodetector 22 at position D1 on the detection panel 21; then the second laser beam with an intensity of P1 illuminates position D2; the third laser beam with an intensity of P2 illuminates position D3; the fourth laser beam with an intensity of P1 illuminates position D5; the fifth laser beam with an intensity of P1 illuminates position D7; the sixth laser beam with an intensity of P2 illuminates position D8; and the seventh laser beam with an intensity of P1 illuminates position D9. Incident light passes sequentially through the second transparent electrode layer 224 and the photosensitive layer 223 and acts on the metal nanowire array 225, exciting surface plasmon resonances on the nanowire structure surface and generating a local electromagnetic field enhancement effect, thereby generating photogenerated electron-hole pairs within the photosensitive layer 223. Under the influence of the built-in electric field, the photogenerated carriers undergo separation and directional transport, causing changes in the amplitude and polarity of the current signals in the first loop 226 and the second loop 227 relative to the initial current, forming corresponding photocurrent signals (see reference). Figure 2 (c) Figure 2 (d) Next, the signal control module acquires the photocurrent signals output by each detector in real time and first determines whether they are within the preset valid range. If the signal is valid, the corresponding incident light intensity is obtained by analyzing the polarity and amplitude of each photocurrent signal, and the incident intensity sequence P2, P1, P2, P1, P1, P2, P1 is restored in chronological order. At the same time, the incident path D1, D2, D3, D5, D7, D8, D9 is obtained by analyzing the position of the detector that generates the photocurrent signal. When the obtained incident intensity, incident intensity sequence, and incident path are all consistent with the system's preset identification logic, the signal control module outputs an unlock control command to make the target device perform an unlock operation; if any parameter does not match, the system determines that the verification has failed and remains locked.

[0041] In this embodiment, the optical security system 100 utilizes an embedded nanowire photodetector 22 to jointly detect the amplitude and polarity of the photocurrent signal generated by the incident light signal. It then combines the incident light intensity sequence and incident path information for multi-dimensional analysis and verification, thereby achieving accurate identification of the optical signal encoding. Compared to existing security methods based on single optical or single electrical signal identification, this invention introduces a verification mechanism combining light intensity encoding and spatial path encoding, and determines the validity of the photocurrent signal. This effectively suppresses the influence of environmental noise and interference signals on the identification process, improving the system's identification accuracy and stability. Simultaneously, the surface plasmon resonance and local electromagnetic field enhancement effect generated by the nanowire array 225 structure significantly enhance the device's response to the incident light signal, enabling different incident light intensities to form distinguishable amplitude and polarity characteristics in the electrical signal, thereby improving the sensitivity and reliability of optical signal encoding identification. Through the aforementioned multi-dimensional encoding and multi-level verification mechanism, optical security control with higher security and stronger anti-interference capabilities can be achieved.

[0042] In a further embodiment, the signal control module determines that the photocurrent signal is valid when the deviation between each current photocurrent signal and its corresponding nominal current value is less than or equal to a preset tolerance threshold. By comparing the deviation between the current photocurrent signal and the corresponding nominal current value, and determining that the photocurrent signal is valid when the deviation is less than or equal to the preset tolerance threshold, environmental noise, stray light interference, and abnormal signals caused by device current fluctuations can be effectively filtered, thereby improving the accuracy and stability of photocurrent signal determination and further enhancing the reliability of the system's optical signal recognition process.

[0043] In this embodiment, by presetting nominal current values ​​for different incident light intensities and limiting the allowable deviation range between the photocurrent signal and the nominal current value, environmental noise, stray light, and interference signals caused by device current fluctuations can be effectively filtered out, improving the accuracy and stability of photocurrent signal determination, thereby enhancing the reliability of the system in identifying incident light intensity and further ensuring the security and anti-interference capability of the optical coding verification process.

[0044] In a further embodiment, when the incident intensity is at the first intensity level, the polarity of the photocurrent signal is the same as the initial current signal, but the amplitude decreases. When the incident intensity is at the second intensity level, the polarity of the photocurrent signal is reversed relative to the initial current signal. By simultaneously utilizing both the change in current polarity and the change in amplitude as signal dimensions to distinguish the incident light intensity, not only can the distinguishability between different light intensity levels be improved, but the impact of environmental noise or device fluctuations on the recognition results can also be reduced, thereby improving the accuracy of incident light intensity analysis and the overall reliability of the system's recognition.

[0045] In a further embodiment, the nanowire array 225 is made of silver, with a thickness of any value between 25nm and 35nm and a width of any value between 90nm and 110nm. That is, the thickness of the nanowire array 225 is 25nm, 30nm, or 35nm, or any other value between 25nm and 35nm, and the width of the nanowire array 225 is 90nm, 100nm, or 110nm, or any other value between 90nm and 110nm. This makes it easier for the nanowire array 225 structure to excite surface plasmon resonance in the target wavelength range, thereby forming a more significant local electromagnetic field enhancement effect around the nanowire array 225 and improving the absorption and utilization efficiency of the photosensitive layer 223 for the incident light signal. Meanwhile, by appropriately controlling the thickness and width parameters of the nanowire array 225, the nanowire array 225 structure can maintain good plasmonic resonance characteristics while ensuring the stability of the device structure and electrical conduction performance. This improves the generation and separation efficiency of photogenerated carriers, enhances the response sensitivity and signal recognition of the embedded nanowire photodetector 22 to changes in incident light intensity, and further improves the detection accuracy and stability of the optical security system 100 in the process of optical signal recognition.

[0046] In a further embodiment, the period of the nanowire array 225 is any value between 950nm and 1050nm. That is, the period of the nanowire array 225 can be 950nm, 1000nm, or 1050nm, or any other value between 950nm and 1050nm. This allows for an appropriate electromagnetic coupling distance between adjacent nanowire arrays 225, which is beneficial for effectively exciting surface plasmon resonance and forming a stable local electromagnetic field enhancement effect when irradiated by incident light. The period parameters within the above range not only enhance the absorption capability of the nanowire array 225 structure for target wavelength light signals and improve the generation efficiency of photogenerated electron-hole pairs in the photosensitive layer 223, but also avoid excessive coupling due to too small a spacing between the nanowire arrays 225 or weakened resonance effect due to too large a spacing. Thus, while ensuring the structural stability of the embedded nanowire photodetector 22, it improves the response sensitivity and signal resolution capability of the embedded nanowire photodetector 22 to incident light signals, further improving the recognition accuracy and reliability of the light intensity encoded information of the optical security system 100.

[0047] In a further embodiment, the photosensitive layer 223 is made of indium arsenide, with a thickness of any value between 110 nm and 130 nm. That is, the thickness of the photosensitive layer 223 can be 110 nm, 120 nm, or 130 nm, or any other value between 110 nm and 130 nm. Utilizing the high light absorption coefficient and excellent carrier migration characteristics of indium arsenide, the incident light is fully absorbed in the photosensitive layer 223, efficiently generating photogenerated electron-hole pairs, thereby improving the photoelectric conversion efficiency of the embedded nanowire photodetector 22. Simultaneously, rationally controlling the thickness of the photosensitive layer 223 can shorten the transmission path of photogenerated carriers while ensuring light absorption capacity, reducing recombination losses. This allows photogenerated carriers to complete separation and transport more quickly under the influence of the built-in electric field, thereby improving the response speed and stability of the photocurrent signal and further enhancing the resolution capability of the embedded nanowire photodetector 22 for different incident light intensities.

[0048] In a further embodiment, both the first transparent electrode layer 222 and the second transparent electrode layer 224 are made of transparent conductive glass, and their thicknesses are any value between 25nm and 35nm. That is, the thicknesses of the first transparent electrode layer 222 and the second transparent electrode layer 224 can be 25nm, 30nm, or 35nm, or any other value between 25nm and 35nm. This ensures that the electrodes have good conductivity while maintaining high light transmittance, allowing incident light to pass smoothly through the transparent electrode layers into the photosensitive layer 223 and act on the nanowire array 225, thereby improving the utilization efficiency of the incident light signal by the embedded nanowire photodetector 22. At the same time, controlling the electrode layer thickness within the above range can also reduce the absorption and reflection loss of the light signal by the electrodes while ensuring the continuity and stability of the electrodes, and reduce the electrode resistance, thereby improving the current transmission efficiency and signal response stability of the embedded nanowire photodetector 22.

[0049] In a further embodiment, the thickness of the substrate 221 is any value between 290nm and 310nm. That is, the thickness of the substrate 221 can be 290nm, 300nm, or 310nm, or any other value between 290nm and 310nm. This can ensure the overall structural stability of the embedded nanowire photodetector 22 while providing good mechanical support and interface flatness for the functional layers above, thereby facilitating the stable deposition and construction of structures such as the first transparent electrode layer 222, the photosensitive layer 223, and the nanowire array 225. At the same time, a reasonable substrate 221 thickness can avoid the problem of increased overall device size and stress accumulation caused by an excessively thick substrate 221, and can also prevent insufficient structural strength or device deformation caused by an excessively thin substrate 221. This improves the structural reliability and fabrication consistency of the embedded nanowire photodetector 22, and further ensures the stability of photoelectric signal output and the reliability of system operation.

[0050] Figure 10 This is a schematic flowchart of a verification and judgment method for an optical security system according to an embodiment of the present invention.

[0051] like Figure 10 As shown, the present invention also provides a verification and judgment method for an optical security system 100 based on an embedded nanowire photodetector 22, which includes the following steps: Step S100: Apply a preset bias voltage to each embedded nanowire photodetector 22 in the detection panel 21, so that the first circuit 226 and the second circuit 227 generate initial current signals respectively. Step S200: Receive the optical signal emitted by the laser encoder 10, and collect the current photocurrent signal generated by the first circuit 226 and the second circuit 227 in real time; Step S300: Determine whether the deviation between each current photocurrent signal and its corresponding nominal current value does not exceed the preset tolerance threshold. If it does not exceed the threshold, the current photocurrent signal is determined to be a valid signal; otherwise, it is determined to be an invalid signal and the verification is terminated. Step S400: Based on the polarity and amplitude variation of the current photocurrent signal, identify the corresponding current incident intensity level and record it in chronological order to form the current incident intensity sequence; Step S500: Record the current incident path sequence based on the spatial position of the triggered embedded nanowire photodetector 22; Step S600: Compare the current incident intensity sequence and the current incident path sequence with the preset incident intensity sequence and the preset incident path, respectively; Step S700: When the current photocurrent signal is a valid signal, the current incident intensity level, the current incident intensity sequence, and the incident path sequence all match, output an unlock command; otherwise, remain locked.

[0052] In this embodiment, by employing the aforementioned verification and judgment method, after the optical security system 100 is started, a preset bias voltage is first applied to the embedded nanowire photodetector 22, enabling the embedded nanowire photodetector 22 to form a stable initial current signal under light-free conditions. The photocurrent signals generated by each circuit are acquired in real time when the laser encoding end 10 emits a light signal. By comparing the deviation of the photocurrent signal with a preset nominal current value, it is possible to effectively determine whether the signal is within the valid range, thereby filtering environmental noise and interference signals and improving the reliability of signal recognition. Furthermore, the incident intensity level is identified by combining the polarity and amplitude changes of the photocurrent signal, and an incident intensity sequence is formed by parsing in chronological order. Simultaneously, the incident path sequence is determined based on the spatial position of the triggered embedded nanowire photodetector 22, thereby achieving multi-dimensional parsing of the incident light signal intensity information and spatial path information. Based on this, the parsed incident intensity level, incident intensity sequence, and incident path sequence are matched and verified with preset recognition logic. Only when all verification conditions are simultaneously met is an unlock command output. This enables a significant improvement in the system's security and anti-interference capabilities through multiple information encoding and verification mechanisms, avoiding the risk of misjudgment caused by a single signal recognition method, thereby enhancing the recognition accuracy and security protection level of the optical security system 100.

[0053] In a further embodiment, the step of identifying the corresponding incident intensity level based on the polarity and amplitude variation of the photocurrent signal further includes: The incident intensity level is determined by a joint determination based on the amplitude difference and polarity difference between the photocurrent signals generated by the first circuit 226 and the second circuit 227. When the amplitude difference or polarity relationship does not meet the preset correspondence, it is determined to be an illegal input signal.

[0054] In this embodiment, by simultaneously utilizing the amplitude difference and polarity difference between the photocurrent signals generated by the first circuit 226 and the second circuit 227 for joint determination when identifying the incident light intensity level, the characteristic information of the dual-circuit output signal of the embedded nanowire photodetector 22 can be fully utilized to perform multi-dimensional cross-verification of the incident light signal. Compared with identification based solely on a single circuit signal, this method can effectively improve the accuracy and stability of incident light intensity level determination. When the amplitude difference or polarity relationship of the photocurrent signals of the two circuits is detected to be inconsistent with the preset correspondence, it can be promptly determined as an illegal input signal, thereby avoiding the impact of abnormal lighting, environmental interference, or malicious light signals on the system identification process, further enhancing the anti-interference capability and security protection capability of the optical security system 100, and improving the overall reliability of identification.

[0055] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0056] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An optical security system based on an embedded nanowire photodetector, characterized in that, include: The laser encoding end is used to emit optical signals of a specific wavelength with switchable incident intensity. The device to be identified includes a detection panel for receiving the optical signal. The detection panel includes multiple embedded nanowire photodetectors arranged in an array. Each embedded nanowire photodetector includes a substrate, a first transparent electrode layer, a photosensitive layer, and a second transparent electrode layer stacked sequentially from bottom to top. The photosensitive layer contains multiple periodically arranged nanowire arrays. The first transparent electrode layer and the nanowire arrays form a first circuit, and the second transparent electrode layer and the nanowire arrays form a second circuit. The applied bias voltage of the first transparent electrode layer is greater than the applied bias voltage of the nanowire arrays, so as to generate initial current signals in the first circuit and the second circuit respectively. When the incident intensity of the optical signal is at different preset intensity levels, the polarity and / or amplitude of the photocurrent signals in the first circuit and the second circuit of the embedded nanowire photodetector are different from the initial current signals. The signal control module is used to acquire each current photocurrent signal, and analyze the current incident intensity sequence and current incident path of the laser encoding end according to the magnitude, polarity and amplitude of the current photocurrent signal. When each current photocurrent signal is valid, the current incident intensity sequence matches the preset incident intensity sequence, and the current incident path matches the preset incident path, an unlocking command is generated and sent.

2. The optical security system based on an embedded nanowire photodetector according to claim 1, characterized in that, The signal control module is used to determine that the photocurrent signal is valid when the deviation between each current photocurrent signal and its corresponding nominal current value is less than or equal to a preset tolerance threshold.

3. The optical security system based on an embedded nanowire photodetector according to claim 2, characterized in that, When the incident intensity is at the first intensity level, the polarity of the photocurrent signal is the same as that of the initial current signal, but the amplitude decreases. When the incident intensity is at the second intensity level, the polarity of the photocurrent signal is reversed relative to the initial current signal.

4. The optical security system based on an embedded nanowire photodetector according to claim 3, characterized in that, The nanowire array is made of silver, with a thickness of any value between 25nm and 35nm and a width of any value between 90nm and 110nm.

5. The optical security system based on an embedded nanowire photodetector according to claim 4, characterized in that, The period of the nanowire array is any value between 950nm and 1050nm.

6. The optical security system based on an embedded nanowire photodetector according to claim 5, characterized in that, The photosensitive layer is made of indium arsenide and has a thickness of any value between 110nm and 130nm.

7. The optical security system based on an embedded nanowire photodetector according to claim 6, characterized in that, Both the first transparent electrode layer and the second transparent electrode layer are made of transparent conductive glass, and their thicknesses are any values ​​between 25nm and 35nm.

8. The optical security system based on an embedded nanowire photodetector according to any one of claims 1-7, characterized in that, The thickness of the substrate is any value between 290nm and 310nm.

9. A verification and judgment method for an optical security system based on an embedded nanowire photodetector as described in any one of claims 1-8, characterized in that, Includes the following steps: A preset bias voltage is applied to each embedded nanowire photodetector in the detection panel to generate initial current signals in the first and second circuits, respectively. It receives the optical signal emitted by the laser encoding end and collects the current photocurrent signals generated by the first and second circuits in real time; Determine whether the deviation between each current photocurrent signal and its corresponding nominal current value does not exceed a preset tolerance threshold. If it does not exceed the threshold, the current photocurrent signal is determined to be a valid signal; otherwise, it is determined to be an invalid signal and the verification is terminated. Based on the polarity and amplitude variation of the current photocurrent signal, the corresponding current incident intensity level is identified and recorded in chronological order to form the current incident intensity sequence. Based on the spatial position of the triggered embedded nanowire photodetector, the current incident path sequence is recorded; The current incident intensity sequence and the current incident path sequence are compared with the preset incident intensity sequence and the preset incident path. When the current photocurrent signal is a valid signal, the current incident intensity level, the current incident intensity sequence, and the incident path sequence all match, an unlock command is output; otherwise, the locked state is maintained.

10. The verification and judgment method according to claim 9, characterized in that, The step of identifying the corresponding incident intensity level based on the polarity and amplitude variation of the photocurrent signal further includes: The incident intensity level is determined by a joint determination based on the amplitude difference and polarity difference between the photocurrent signals generated by the first circuit and the second circuit, and an illegal input signal is determined when the amplitude difference or polarity relationship does not meet the preset correspondence.

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