Laser eavesdropping defense and alarm system

Abstract

This application relates to the field of information security and discloses a laser eavesdropping defense and alarm system. The system includes a microwave absorbing and power-generating layer and a laser eavesdropping defense circuit. The microwave absorbing and power-generating layer includes a substrate and a microwave absorbing and power-generating material at least partially covering the substrate. The microwave absorbing and power-generating layer is configured to absorb infrared and / or near-infrared light waves and convert the infrared and / or near-infrared light waves into electrical signals. The microwave absorbing and power-generating layer is uniformly divided into n regions. The laser eavesdropping defense circuit is coupled to the microwave absorbing and power-generating layer and is configured to receive the electrical signals emitted by the microwave absorbing and power-generating layer. The laser eavesdropping defense circuit detects voltage changes in each region of the microwave absorbing and power-generating layer. The system of this application can effectively prevent laser eavesdropping.

Description

Technical Field

[0001] This application relates to the interdisciplinary fields of information security and optoelectronic materials, specifically to a laser eavesdropping defense and alarm system. Background Technology

[0002] In recent years, laser eavesdropping technology has become a major threat to high-level information espionage due to its non-contact detection characteristics and long-range information interception capabilities. This technology, by modulating the acoustic vibration information in a reflected laser beam, can reconstruct voice signals within a range of 500 meters to 1 kilometer, posing a significant security risk to high-value targets such as military command centers and classified offices.

[0003] Current protection systems primarily employ passive laser blocking solutions, which involve applying a composite laser protection film to the surface of building windows. Typically, this film utilizes a metal oxide nanoparticle doping process, achieving a transmission attenuation rate of up to 99% for lasers in the 800-1600nm wavelength range. However, engineering practice has revealed the following structural defects in this traditional approach:

[0004] (1) This type of laser film requires pre-installation and film application. The glass of the room to be protected must be covered with a metal oxide or ITO composite film to attenuate near-infrared transmission. However, this solution only provides one-way shielding and cannot detect attacks. (2) The entire window needs to be covered with film, resulting in high installation and maintenance costs. In addition, the heat absorption and temperature rise will affect indoor comfort. (3) The appearance difference is obvious, which may expose the protection position and become an identification mark of high-value targets. (4) This film has a limited lifespan and needs to be replaced regularly.

[0005] Another approach utilizes an independent photodetector array, which collects laser echo signals by placing InGaAs (indium gallium arsenide) detectors inside the window. The problems are: (1) It requires external power supply and is prone to dead zones. (2) It may still be breached when the laser sweeps through an area where no detectors are placed.

[0006] Another type of electrochromic / liquid crystal dimming glass attempts to interfere with echoes by rapidly changing the transmittance, but it suffers from problems such as slow response speed, short lifespan, and inability to locate.

[0007] More importantly, existing technologies are essentially one-way protection mechanisms, lacking the ability to detect and respond to attack events. When subjected to laser eavesdropping attacks, the system is unable to locate the attack source or trigger real-time alarms, resulting in a serious lag in security protection.

[0008] In summary, the current technical pain points in this field are as follows: (1) Traditional film layers and dimming glass lack event detection and alarm capabilities. (2) Existing detector solutions mostly use "present / absent" judgment, which cannot invert the laser incident angle and makes it difficult to trace the attack source. (3) External power supply and conspicuous equipment damage the integrated appearance of the window and result in high maintenance costs. (4) Large-area building facades require flexible assembly, replacement and link cascading. Summary of the Invention

[0009] The purpose of this application is to provide a laser eavesdropping defense and alarm system that can effectively prevent laser eavesdropping.

[0010] This application discloses a laser eavesdropping defense and alarm system, including:

[0011] A microwave absorbing power generation layer includes a substrate and a microwave absorbing power generation material at least partially covering the substrate. The microwave absorbing power generation layer is configured to absorb light waves to generate electricity and to convert infrared light and / or near-infrared light waves into electrical signals. The microwave absorbing power generation layer is uniformly divided into n regions.

[0012] A laser eavesdropping defense circuit is coupled to the microwave absorbing power generation layer. The laser eavesdropping defense circuit is configured to receive electrical signals emitted by the microwave absorbing power generation layer, wherein the laser eavesdropping defense circuit detects voltage changes in each region of the microwave absorbing power generation layer.

[0013] In a preferred embodiment, when the electrical signals emitted by one or more of the n anti-eavesdropping detection sub-regions exceed the preset threshold, it is determined that the area has been irradiated by a laser.

[0014] In a preferred embodiment, the laser eavesdropping defense circuit detects voltage changes in each region of the absorbing power generation layer.

[0015] In a preferred embodiment, each of the n anti-eavesdropping detection sub-regions independently emits an electrical signal.

[0016] In a preferred embodiment, 4≤n≤256, each sub-region outputs photovoltaic power under natural light conditions, while simultaneously converting incident light in the 800nm–1600nm band into a detection electrical signal.

[0017] In a preferred embodiment, the microwave absorbing and power generating layer is an 8×8 grid.

[0018] In a preferred embodiment, a multi-channel sampling module is also included, which is electrically connected to each of the sub-regions to collect voltage / current changes in each of the sub-regions.

[0019] In a preferred embodiment, it also includes: a specially made grating layer;

[0020] When the microwave absorbing power generation material partially covers the substrate, the specially designed grating layer is arranged parallel to the outer and / or inner sides of the microwave absorbing power generation layer. The specially designed grating layer is configured to scatter or diffract and enhance the infrared and / or near-infrared light irradiated onto the microwave absorbing power generation layer, preventing the infrared and / or near-infrared light from passing through the portion of the substrate not covered by the microwave absorbing power generation material.

[0021] In a preferred embodiment, the specially designed grating layer produces diffraction or scattering phenomena for light waves in the wavelength range of 800nm-1600nm.

[0022] In a preferred embodiment, the specially designed grating layer has a transmittance of ≥60% for wavelengths in the range of 400nm–700nm and a diffraction-scattering efficiency of ≥45% for wavelengths in the range of 800–1600nm, which is used to enhance near-infrared laser scattering and suppress its transmission.

[0023] In a preferred embodiment, the laser eavesdropping defense circuit includes electrically connected components:

[0024] A photoelectric signal receiving module is used to receive electrical signals generated by the wave-absorbing power generation layer under the illumination of infrared light and / or near-infrared light, wherein the electrical signals are caused by the illumination of infrared light and / or near-infrared light;

[0025] A signal amplification module, coupled to the photoelectric signal receiving module, is used to amplify the electrical signal;

[0026] The signal processing module is used to analyze the amplified electrical signal and convert it into a voltage signal.

[0027] In a preferred embodiment, the inner side of the microwave absorbing and power generating layer is further provided with a hollow layer and a detection layer in sequence from the outside to the inside, wherein the thickness of the hollow layer is L.

[0028] In a preferred embodiment, the infrared light and / or near-infrared light irradiates the microwave absorbing power generation layer to form a first light spot, the first light spot being circular or elliptical depending on the incident angle of the laser.

[0029] In a preferred embodiment, the detection layer receives infrared and / or near-infrared light transmitted by the hollow layer and forms a second light spot, the second light spot being circular or elliptical depending on the incident angle of the laser.

[0030] In a preferred embodiment, the wave-absorbing power generation layer is divided into n regions in a longitudinal, transverse, or grid pattern, and each region is connected by a flexible cable.

[0031] In a preferred embodiment, the microwave absorbing power generation material includes one or more of the following materials:

[0032] Silicon-germanium alloy, indium gallium arsenide, germanium, cadmium telluride.

[0033] In a preferred embodiment, the laser eavesdropping defense and alarm system is configured as a modular structural unit. Multiple modular structural units are spliced ​​together by detachable mechanical connecting components to form a continuous protective layer covering the exterior facade of the building. The laser eavesdropping defense circuit transmits signals across modules through a bus architecture to form a distributed monitoring network covering the exterior surface of the building.

[0034] In this application, the laser eavesdropping defense and alarm system fundamentally breaks through the limitations of traditional one-way protection mechanisms and overcomes the deficiency of lacking attack event detection and response capabilities. In existing technologies, when a system is subjected to a laser eavesdropping attack, it often cannot locate the attack source in real time, nor can it trigger a timely alarm, resulting in serious lag and blind spots in security protection. This application, however, divides the absorbing power generation layer into multiple independent areas. When a laser irradiates the absorbing power generation layer, the laser light wave is converted into an electrical signal through the photoelectric effect. Combined with the laser eavesdropping defense circuit, the voltage changes in each area are detected in real time, enabling the system to accurately locate the position and intensity of the laser irradiation. Simultaneously, the system can immediately trigger an alarm mechanism when laser eavesdropping occurs, responding in real time and recording the attack event, providing a more efficient and timely response capability for security protection, and greatly improving the reliability and real-time performance of laser eavesdropping defense.

[0035] Furthermore, by setting a special grating layer, this application not only enhances the system's protection against infrared and near-infrared light, but also effectively prevents laser light waves from passing through the substrate portion not covered by the microwave absorbing and power-generating material, thereby enhancing the overall protection performance.

[0036] Furthermore, the system of this application adopts a modular structure, enabling its flexible application to different protection scenarios, such as the protection needs of large areas like building facades. Through detachable mechanical connections and bus-based signal transmission, the system can form a distributed monitoring network, ensuring real-time monitoring and collaborative protection of various areas. Additionally, due to the overall modular design, system maintenance and replacement are very convenient; any module can be quickly replaced if it malfunctions, without dismantling the entire system. Moreover, all modules have a consistent appearance, avoiding obvious markings on building facades. This prevents the exposure of protective facilities in important locations, thus preventing potential attackers from identifying them based on appearance and developing targeted attack strategies, further enhancing the system's concealment and security.

[0037] The specification of this application contains numerous technical features distributed across various technical solutions. Listing all possible combinations of these technical features (i.e., technical solutions) would make the specification excessively lengthy. To avoid this problem, the various technical features disclosed in the above-described invention, the various technical features disclosed in the following embodiments and examples, and the various technical features disclosed in the accompanying drawings can be freely combined to form various new technical solutions (all of which are considered to have been described in this specification), unless such a combination of technical features is technically infeasible. For example, one example discloses feature A+B+C, and another example discloses feature A+B+D+E. Features C and D are equivalent technical means that serve the same function, and technically only one needs to be used; they cannot be used simultaneously. Feature E can technically be combined with feature C. Therefore, the solution A+B+C+D should not be considered as described because it is technically infeasible, while the solution A+B+C+E should be considered as described. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of a laser eavesdropping defense and alarm system according to one embodiment of this application.

[0039] Figure 2 This is a schematic diagram of the partitioning of the microwave absorbing power generation layer of a laser eavesdropping defense and alarm system according to one embodiment of this application.

[0040] Figure 3 This is a schematic diagram of a laser eavesdropping defense circuit of a laser eavesdropping defense and alarm system according to one embodiment of this application.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1-Substrate, 2-Absorbing and power-generating material, 3-Special grating layer, 4-Hollow layer, 5-Detection layer Detailed Implementation

[0043] In the following description, many technical details are presented to help the reader better understand this application. However, those skilled in the art will understand that the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0044] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0045] The first embodiment of this application relates to a laser eavesdropping defense and alarm system, the structural diagram of which is shown below. Figure 1As shown, it includes: a photoelectric conversion module for absorbing laser light, the photoelectric conversion module for absorbing laser light including a microwave absorbing power generation layer, the microwave absorbing power generation layer including a substrate and a microwave absorbing power generation material at least partially covering the substrate, the microwave absorbing power generation layer being configured to absorb light waves to generate electricity, and to convert infrared light and / or near-infrared light waves into electrical signals, the microwave absorbing power generation layer being uniformly divided into n anti-eavesdropping detection sub-regions (e.g., Figure 2 (as shown), where n≥4; and

[0046] A laser eavesdropping defense circuit, coupled to a photoelectric conversion module for absorbing laser light, is configured to receive electrical signals emitted from one or more of the eavesdropping detection sub-regions, wherein the laser eavesdropping defense circuit detects voltage changes in each region of the absorbing power generation layer.

[0047] In an optional embodiment, a specially designed grating layer may also be included. When the microwave-absorbing power-generating material partially covers the substrate, the specially designed grating layer is arranged parallel to the outer and / or inner side of the microwave-absorbing power-generating layer. The specially designed grating layer is configured to scatter or diffract and enhance infrared and / or near-infrared light incident on the microwave-absorbing power-generating layer, preventing infrared and / or near-infrared light from passing through the portion of the substrate not covered by the microwave-absorbing power-generating material. The specially designed grating layer produces diffraction or scattering phenomena for light waves in the wavelength range of 800nm-1600nm.

[0048] Optionally, when the specially designed grating layer is configured to produce diffraction phenomena for infrared and / or near-infrared light, the fabrication method of the special grating layer is as follows: It is achieved by introducing periodic refractive index changes in a transparent photosensitive polymer substrate (such as polymethyl methacrylate PMMA). First, a photosensitive material is uniformly coated onto the substrate and dried at a temperature of 80°C to 100°C to remove the solvent. Next, using a two-beam laser interferometry technique, interference fringes (typically with a period of about 500 nm) satisfying a diffraction period at a wavelength of 1150 nm are generated by adjusting the incident angle of the laser and controlling the exposure time, thereby producing periodic refractive index changes in the material. Then, a development process is performed to remove unexposed areas to enhance refractive index contrast. Finally, the grating structure is fixed by thermosetting to ensure significant diffraction effects at the preferred wavelength of 1150 nm.

[0049] Optionally, when the specially designed grating layer is configured to scatter infrared and / or near-infrared light, the scattering grating can be a multi-scale surface structure grating or a random microstructure scattering grating. The fabrication method of the multi-scale surface structure grating is as follows: A multi-scale structure scattering grating is used, consisting of a micrometer-scale periodic structure (approximately 500 nm) and a nanometer-scale random rough structure (50-200 nm). The fabrication process is as follows: First, a high-transmittance transparent substrate (such as quartz glass or PMMA) is selected, and photoresist is coated onto its surface. The photoresist thickness is controlled uniformly using a spin-coating process. A grating structure with a period of approximately 500 nm is generated on the substrate surface using dual-beam laser interference exposure to match the scattering requirement of 1150 nm. Then, a periodic stripe mask is obtained using development processing. Next, reactive ion etching (RIE) with a depth of approximately 200-300 nm is performed to form a large-scale periodic structure. Subsequently, a 50-200 nm nanometer-scale random rough structure is introduced through methods such as HF etching or oxygen plasma bombardment to further enhance the scattering effect. The final grating structure exhibits significant scattering effects near 1150 nm while maintaining over 70% transmittance for visible light (400-700 nm), meeting the requirements for near-infrared scattering applications. The fabrication method of the random microstructure scattering grating is as follows: A random microstructure scattering grating is fabricated on a transparent substrate (such as quartz glass or PMMA). First, high-refractive-index nanoparticles (such as titanium dioxide TiO2) with a particle size of 50 nm to 150 nm are prepared into a suspension with a mass fraction of 1 wt%. Approximately 1% of the nanoparticle mass of a dispersant (such as PVP) is added, and the suspension is ultrasonically treated for 30 minutes to ensure uniform dispersion. Then, the nanoparticles are uniformly coated onto the substrate surface using a spin-coating method at 2000 rpm for 60 seconds, forming a random nanostructure layer with a thickness of approximately 100 nm and a surface coverage of 10% to 30%. Next, the coating is dried at 80°C for 30 minutes and then heat-treated at 150°C for 1 hour to enhance its stability. The resulting scattering grating exhibits a strong scattering effect on light with a wavelength of 1150nm (reducing the intensity of scattered light by more than 50%), while maintaining a transmittance of more than 80% in the visible light range (400nm to 700nm), successfully achieving the goal of effectively scattering near-infrared light while maintaining high transmittance of visible light.

[0050] In an optional embodiment, the laser eavesdropping defense circuit may include electrically connected:

[0051] The photoelectric signal receiving module is used to receive electrical signals generated by the absorbing power generation layer under infrared and / or near-infrared light irradiation. The electrical signals are caused by infrared and / or near-infrared light irradiation.

[0052] The signal amplification module is coupled to the photoelectric signal receiving module to amplify electrical signals.

[0053] The signal processing module is used to analyze the amplified electrical signal and convert it into a voltage signal.

[0054] The laser eavesdropping defense circuit can employ a shunt detection method, connecting the input terminal of the laser eavesdropping defense circuit to the output terminal of the absorbing and generating layer, and then connecting it in parallel with the load. The laser eavesdropping defense circuit also includes an electrical signal detection module composed of a current-sensing resistor and an operational amplifier. The current-sensing resistor is a precision low-resistance resistor used to detect the passing current and voltage. The operational amplifier uses a differential amplifier to amplify the voltage difference across the current-sensing resistor, thereby obtaining the change signal of the photocurrent.

[0055] In an optional embodiment, such as Figure 3 As shown, the laser eavesdropping defense circuit can also be implemented in the following way: an analog front-end that collects photovoltaic signals and controls the bias calibration of n areas, in conjunction with back-end digital logic (CPLD / MCU, etc.), mainly collects and processes signals from the absorbing power generation layer (the weak voltage / current output after being irradiated by near-infrared or infrared light). Specifically, it can be divided into several modules: input and preprocessing module, bias calibration module, analog multiplexing / switching module, sampling / holding and precision amplification module, and digital interface and back-end control module.

[0056] The input and preprocessing module acquires photovoltaic signals from n regions of the absorbing photovoltaic layer. These signals originate from the weak voltage / current generated by the absorbing photovoltaic layer after being irradiated with near-infrared or infrared light. This module performs preliminary signal shaping, protection, and filtering to eliminate noise and interference. The bias calibration module uses digital-to-analog conversion to perform gain or bias calibration on each channel, as the signal range of the absorbing photovoltaic layer may differ under different light intensities; calibration further improves measurement accuracy. The multiplexing / switching module selects one channel from multiple channels or switches them in a certain sequence, transmitting the signal to the sampling / holding and precision amplification module. This module precisely amplifies, filters, or latches the signal level to reduce noise interference and ensure the accuracy of subsequent signal processing. Finally, the processed signal can be used to determine and trigger alarm and other response actions.

[0057] Under visible light conditions, the absorbing power generation layer typically receives natural light and performs normal photoelectric conversion. At this time, the current and voltage values ​​detected by the information processing unit remain relatively stable within a certain range, constituting the system's "normal" operating state. Specifically, the absorbing power generation layer can convert visible light into electrical energy through the known photovoltaic effect, and its output current and voltage have stable reference levels under normal conditions without laser interference.

[0058] When exposed to external laser light, the absorption layer will experience significant current or voltage fluctuations within a short period due to the substantial differences in wavelength, intensity, or incident angle compared to normal visible light conditions. This is because lasers have higher energy densities or different spectral characteristics; when they irradiate the absorption layer, they instantly increase the amplitude or rate of photoelectric conversion output, causing a rapid rise or violent fluctuation in the instantaneous value of current or voltage.

[0059] In an optional embodiment, the electrical signals generated by the n regions of the absorbing power generation layer are sampled in real time by built-in sensors and converted into digital signals by an analog-to-digital converter module to form a continuous voltage fluctuation data sequence.

[0060] In an optional embodiment, a hollow layer and a detection layer may be sequentially provided from the outside to the inside of the microwave absorbing and power generating layer, wherein the thickness of the hollow layer is L. Infrared light and / or near-infrared light irradiates the microwave absorbing and power generating layer to form a first light spot, which is circular or elliptical depending on the incident angle of the laser. The detection layer receives the infrared light and / or near-infrared light transmitted from the hollow layer and forms a second light spot, which is also circular or elliptical depending on the incident angle of the laser.

[0061] In one optional embodiment, the microwave absorbing power generation layer is divided into n regions in a longitudinal, transverse, or grid pattern, and each region is connected by flexible cabling. Each region can have an independent power generation unit and signal acquisition interface.

[0062] In one optional embodiment, the microwave absorbing power generation material includes one or more of the following materials: silicon-germanium alloy, indium gallium arsenide, germanium, and cadmium telluride.

[0063] In an optional embodiment, an electrically connected alarm module may also be included, which issues an alarm signal when the electrical signal or voltage changes beyond a preset threshold.

[0064] In an optional embodiment, the laser eavesdropping defense and alarm system is configured as a modular structural unit. Multiple modular structural units are spliced ​​together by detachable mechanical connecting components to form a continuous protective layer covering the exterior facade of the building. The laser eavesdropping defense circuit transmits signals across modules through a bus architecture to form a distributed monitoring network covering the exterior surface of the building.

[0065] To better understand the technical solution of this application, a specific example is provided below. The details listed in this example are mainly for ease of understanding and are not intended to limit the scope of protection of this application.

[0066] The laser eavesdropping defense and alarm system in this embodiment employs a microwave-absorbing and power-generating layer. This layer consists of a transparent or semi-transparent substrate, and its surface is partially or completely covered with microwave-absorbing and power-generating materials (such as silicon-germanium alloy, indium gallium arsenide, germanium, or cadmium telluride). These materials have the ability to efficiently absorb infrared and near-infrared light waves and convert them into electrical signals. To achieve regional monitoring, the microwave-absorbing and power-generating layer is uniformly divided into several independent areas. Each area can independently generate a voltage fluctuation curve that changes over time. These areas are interconnected by flexible cabling, thereby ensuring the stability of signal transmission and the consistency of appearance, avoiding the exposure of important protective facilities. The flexible cabling not only makes the signal acquisition of each area independent and free from interference, but also facilitates the rapid replacement and maintenance of system modules.

[0067] To further enhance protection against laser eavesdropping attacks, this embodiment incorporates a specially designed grating layer on the outer and / or inner sides of the microwave absorbing and power-generating layer. When the microwave absorbing and power-generating material only partially covers the substrate, the grating layer can scatter or diffract and enhance the infrared and near-infrared light irradiating the microwave absorbing and power-generating layer, preventing laser waves from passing through the portion not covered by the absorbing material and directing more laser energy into the microwave absorbing and power-generating area. This grating layer utilizes techniques such as photolithography, nanoimprinting, or laser interference to form periodic or non-periodic micron- or nanometer-scale structures on a transparent substrate. Its period is typically set between 200 nm and 600 nm, specifically targeting light waves in the 800 nm to 1600 nm wavelength range (preferably 1150 nm) to produce significant diffraction or scattering effects, thereby further improving the overall laser absorption efficiency.

[0068] Inside the microwave absorbing and power generating layer, a hollow glass layer and a detection layer are sequentially arranged. When a laser beam irradiates the microwave absorbing and power generating layer, the photoelectric effect causes the layer to generate an electrical signal. Simultaneously, the laser beam passes through the microwave absorbing and power generating layer and forms a first light spot on the hollow glass layer. The size and shape (circular or elliptical) of this light spot are affected by the laser incident angle. Subsequently, the laser continues to pass through the hollow glass layer and irradiates the detection layer, forming a second light spot on the detection layer. Although this embodiment does not use the incident angle as the primary criterion, analyzing the relative positional changes between the first and second light spots (e.g., using the geometric relationship between interlayer distance and offset) can still provide some auxiliary information to help identify the laser irradiation area.

[0069] The laser eavesdropping defense circuit is coupled to the microwave absorbing power generation layer to detect voltage changes in different areas of the layer in real time. When the layer is generating electricity normally under visible light, the current and voltage detected by the system remain within a stable reference range. However, when laser irradiation occurs, the high energy density and specific wavelength characteristics of the laser significantly enhance the photoelectric effect, causing sudden or continuous abnormal fluctuations in the voltage signal of the corresponding area. This circuit may include hardware such as a photoelectric signal receiving module, a signal amplification module, and an analog-to-digital conversion module. It performs digital filtering and other operations on the acquired digital signal and compares whether the voltage change exceeds a preset threshold.

[0070] The laser eavesdropping defense and alarm system of this application adopts a modular design. Each individual module is spliced ​​together to form a continuous protective layer through detachable mechanical connecting components, and cross-module signal transmission is realized through a bus architecture, forming a distributed monitoring network. Since each module has a consistent appearance and modular characteristics, replacement and maintenance are very convenient. At the same time, it will not form obvious marks on the building facade due to different appearances, thereby preventing targeted and precise eavesdropping by the eavesdropper.

[0071] Overall, this embodiment, through multi-layered optical structure design, regionalized signal acquisition, advanced digital signal processing, and modular system construction, achieves real-time detection, precise positioning, alarm, and event recording of laser eavesdropping, significantly improving the comprehensive protection capability and reliability of the laser eavesdropping defense and alarm system, and is no longer limited to passive eavesdropping defense.

[0072] It should be noted that in this patent application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this patent application, if it refers to performing an action according to an element, it means performing the action at least according to that element, including two cases: performing the action only according to that element, and performing the action according to that element and other elements. Expressions such as "multiple," "repeatedly," and "various" include two, two times, two kinds, and more than two, more than two times, and more than two kinds.

[0073] This specification includes combinations of various embodiments described herein. Individual references to embodiments are made (e.g., "one embodiment," "some embodiments," or "preferred embodiments"); however, these embodiments are not mutually exclusive unless indicated to be mutually exclusive or are readily apparent to those skilled in the art. It should be noted that the word "or" is used in a non-exclusive sense throughout this specification unless the context explicitly indicates or requires it.

Claims

1. A laser eavesdropping defense and alarm system, characterized in that, include: A photoelectric conversion module for absorbing laser light includes a wave-absorbing power generation layer. The wave-absorbing power generation layer includes a substrate and a wave-absorbing power generation material that covers at least partially on the substrate. The wave-absorbing power generation layer is configured to absorb light waves to generate electricity and to convert infrared light and / or near-infrared light waves into electrical signals. The wave-absorbing power generation layer is divided into n anti-eavesdropping detection sub-regions, where n≥4. and A laser eavesdropping defense circuit is coupled to the photoelectric conversion module for absorbing laser light. The laser eavesdropping defense circuit is configured to receive electrical signals emitted from one or more of the n anti-eavesdropping detection sub-regions, wherein the laser eavesdropping defense circuit detects voltage changes in each region of the absorbing power generation layer.

2. The laser eavesdropping defense and alarm system as described in claim 1, characterized in that, Also includes: Special grating layer; When the microwave absorbing power generation material partially covers the substrate, the specially designed grating layer is arranged parallel to the outer and / or inner sides of the microwave absorbing power generation layer. The specially designed grating layer is configured to scatter or diffract and enhance the infrared and / or near-infrared light irradiated onto the microwave absorbing power generation layer, preventing the infrared and / or near-infrared light from passing through the portion of the substrate not covered by the microwave absorbing power generation material.

3. The laser eavesdropping defense and alarm system as described in claim 2, characterized in that, The specially designed grating layer produces diffraction or scattering phenomena for light waves in the wavelength range of 800nm-1600nm.

4. The laser eavesdropping defense and alarm system as described in claim 1, characterized in that, The laser eavesdropping defense circuit includes electrically connected components: A photoelectric signal receiving module is used to receive electrical signals generated by the wave-absorbing power generation layer under the illumination of infrared light and / or near-infrared light, wherein the electrical signals are caused by the illumination of infrared light and / or near-infrared light; A signal amplification module, coupled to the photoelectric signal receiving module, is used to amplify the electrical signal; The signal processing module is used to analyze the amplified electrical signal and convert it into a voltage signal.

5. The laser eavesdropping defense and alarm system as described in claim 1, characterized in that, The inner side of the microwave absorbing and power generating layer is further provided with a hollow layer and a detection layer in sequence from the outside to the inside, wherein the thickness of the hollow layer is L.

6. The laser eavesdropping defense and alarm system as described in claim 1, characterized in that, The infrared light and / or near-infrared light irradiate the microwave absorbing and power generating layer to form a first light spot, which is circular or elliptical depending on the incident angle of the laser.

7. The laser eavesdropping defense and alarm system as described in claim 5, characterized in that, The detection layer receives infrared and / or near-infrared light transmitted by the hollow layer and forms a second light spot, which is circular or elliptical depending on the incident angle of the laser.

8. The laser eavesdropping defense and alarm system as described in claim 1, characterized in that, The microwave absorbing and power generation layer is divided into n regions in a longitudinal, transverse, or grid pattern, and each region is connected by a flexible cable.

9. The laser eavesdropping defense and alarm system as described in claim 1, characterized in that, The microwave absorbing power generation material includes one or more of the following materials: Silicon-germanium alloy, indium gallium arsenide, germanium, cadmium telluride.

10. The laser eavesdropping defense and alarm system as described in claim 1, characterized in that, The laser eavesdropping defense and alarm system is configured as a modular structural unit. Multiple modular structural units are spliced ​​together by detachable mechanical connecting components to form a continuous protective layer covering the exterior of the building. The laser eavesdropping defense circuit transmits signals across modules through a bus architecture, forming a distributed monitoring network covering the exterior surface of the building.

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