Capacitive PIR pyroelectric sensor

Abstract

The utility model discloses a capacitive PIR pyroelectric sensor, which comprises a metal shell, a metal base, a power supply pin, a signal pin, an infrared filter, a light transmission clamping plate, a light diffusion sheet, a ceramic substrate, an infrared inductor capacitor, an inductor bracket capacitor, a circuit board and an MOS (Metal Oxide Semiconductor) tube, and is characterized in that the inductor bracket capacitor is provided with a rectangular ceramic substrate; a U-shaped infrared sensitive material is printed on the ceramic substrate, and an infrared inductor is formed through a sintering process; and the inductor and the support capacitor form an infrared inductor capacitor with an asymmetric polar plate structure. The light diffusing sheet refracts or reflects an infrared signal passing through the infrared filter to the inductor capacitance plate, a power supply of the PIR pyroelectric sensor is input through the power supply pin, and an infrared induction signal is amplified by the MOS tube and output through the middle signal pin. According to the capacitive PIR pyroelectric sensor provided by the utility model, the sensitivity and the reliability of the sensor are remarkably improved by optimizing the structure of the inductor, improving the manufacturing process and adopting the advanced packaging technology.

Description

Technical Field

[0001] This utility model relates to a capacitive PIR (passive infrared) pyroelectric sensor, specifically its structural design and manufacturing method. This sensor is suitable for security, smart home, and other fields, and is used to detect changes in infrared radiation from the human body or other objects. Background Technology

[0002] Existing PIR pyroelectric sensors have certain limitations in terms of sensitivity, signal processing, and anti-interference capabilities. Traditional sensors typically employ simple inductive structures and relatively crude manufacturing processes, resulting in unstable performance, especially in applications under complex environments. Furthermore, the packaging methods and material choices of existing sensors also affect their durability and reliability.

[0003] To address the aforementioned issues, this invention proposes a novel capacitive PIR pyroelectric sensor. By optimizing the sensor structure, improving the manufacturing process, and employing advanced packaging technology, the sensor's sensitivity and reliability are significantly enhanced. Summary of the Invention

[0004] To solve the above-mentioned technical problems, this application provides the following technical solution:

[0005] U-shaped infrared sensing material: This material is sintered on a ceramic substrate to form an asymmetric electrode infrared sensor capacitor (5-1U and 5-2U). The U-shaped material has a width of 0.5mm to 2mm and a thickness of 0.05-0.15mm, and is optimized for best performance.

[0006] Astigmatism filter design: The astigmatism filter is located below the infrared filter. It refracts or reflects the infrared signal passing through the filter onto the capacitor plate of the sensor, significantly improving the reception efficiency of the infrared signal.

[0007] MOSFET signal amplification: MOSFETs are used to amplify infrared sensing signals and output them through intermediate signal pins to ensure high-fidelity signal transmission.

[0008] Metal casing and inert gas encapsulation: The metal casing is welded and sealed in a closed environment, and the sensor is simultaneously filled with protective inert gas (such as argon or nitrogen) to improve the sensor's durability and stability.

[0009] Ceramic substrate and capacitor structure: U-shaped infrared sensitive material is printed on the ceramic substrate to form a new asymmetric plate infrared sensor capacitor, which is connected at both ends through the bottom electrode and supported by the sensor support capacitor.

[0010] This utility model provides a capacitive PIR pyroelectric sensor, comprising the following components and features:

[0011] Metal casing: Used to protect internal components and prevent external interference.

[0012] Metal base: Supports the entire sensor and provides pin connections.

[0013] Power supply pins and signal pins: used for input power and output signals.

[0014] Infrared filter: Improves infrared transmittance and filters out unwanted light.

[0015] Optical pass plate: Used to fix infrared filters and diffusers.

[0016] Astigmatism filter: refracts or reflects infrared signals that have passed through the infrared filter onto the capacitor plates of the sensor.

[0017] Ceramic substrate: serving as the base for the capacitor that supports the inductor.

[0018] Infrared sensor capacitor: formed by sintering a U-shaped infrared-sensitive material onto a ceramic substrate.

[0019] Sensor support capacitor: Connects to the U-shaped infrared capacitor electrode plate, located at both ends of the ceramic substrate.

[0020] Circuit board: Connects power supply pins and signal pins, and installs MOSFETs for signal amplification.

[0021] MOSFET: Used to amplify infrared sensing signals.

[0022] Specific features:

[0023] The capacitor in the sensor support is provided with a rectangular ceramic substrate;

[0024] The ceramic substrate is printed with a U-shaped infrared-sensitive material, which is sintered on the ceramic substrate to form an infrared sensor.

[0025] The U-shaped infrared sensitive material has a width of 0.5mm to 2mm and a thickness of 0.05-0.15mm;

[0026] The sensor support is capacitively connected to the U-shaped infrared capacitor electrode plate, located at both ends of the ceramic substrate.

[0027] The infrared sensor and the support capacitor together form an asymmetric plate infrared sensor capacitor with capacities of 5-1U and 5-2U.

[0028] The aforementioned diffuser will refract or reflect the infrared signal passed through the infrared filter onto the capacitor plate of the inductive element;

[0029] The power supply for the PIR pyroelectric sensor is input through the power supply pin, and the infrared sensing signal is amplified by a MOSFET and output through the intermediate signal pin.

[0030] Preferably, wherein:

[0031] The infrared filter and diffuser are located on the upper and lower sides of the optical pass card, embedded in the top window of the metal shell, fixed with black resin glue, and encapsulated inside the metal shell of the sensor.

[0032] The infrared filter is made of coated monocrystalline silicon wafer to improve infrared transmittance.

[0033] Preferably, wherein:

[0034] The surface of the diffuser has a semi-circular groove, and the upper and lower pieces are deflected by 90° and combined together, forming an interlaced corrugated reflective surface in the horizontal and vertical directions inside.

[0035] The spacing of the corrugated reflective surfaces is 0.1 mm to 0.5 mm, which helps to improve the reception efficiency of infrared signals.

[0036] Preferably, wherein:

[0037] The infrared sensor capacitor has a U-shaped symmetrical structure with forks distributed in the center of the ceramic substrate, and the two ends are connected to the sensor support capacitor through the bottom electrode.

[0038] The interdigitation distance of the U-shaped symmetrical structure is 0.2 mm to 0.8 mm to optimize capacitor performance.

[0039] Preferably, wherein:

[0040] The U-shaped symmetrical capacitor body plates are printed with a protective film and sintered on a ceramic substrate.

[0041] The U-shaped symmetrical capacitor has a rectangular groove in the middle plate and a semi-circular groove in the middle of the two side plates.

[0042] After the U-shaped symmetrical capacitor plate is polarized, it is welded to the inductor support capacitor through metal electrodes at both ends.

[0043] The protective film is made of specific materials (such as silicon nitride or zirconium oxide) to improve durability and stability.

[0044] Preferably, wherein:

[0045] The sensor support capacitor is rectangular with a concave center, and the electrodes at both ends are respectively connected to the infrared sensor capacitor plate and the auxiliary fixing end, and are welded to the ceramic substrate.

[0046] The capacitor connection electrodes of the inductor support are made of highly conductive materials (such as copper or silver) to improve the reliability of the electrical connection.

[0047] Preferably, wherein:

[0048] The power supply pins and signal pins are led out from under the metal base and arranged in a circular pattern. The distance from the pins to the center of the metal base is 2.54 mm.

[0049] The pins are gold-plated to improve corrosion resistance and conductivity.

[0050] Preferably, wherein:

[0051] The method and steps for manufacturing the pyroelectric inductor of the sensor include:

[0052] Step 1: Grind the pyroelectric inductor ceramic powder, filter it with a 500-mesh steel screen, and prepare the inductor slurry;

[0053] Step 2: Print a conductive paste with a thickness of 0.5-12μm on a ceramic plate to fabricate the inductive body electrode;

[0054] Step 3: Print the pyroelectric inductor underlayer protective film on the ceramic and dry and cure at 160°C;

[0055] Step 4: Print a pyroelectric inductor ceramic paste with a thickness of 0.05-0.15mm on the bottom protective film to form a U-shaped capacitor plate;

[0056] Step 5: Sinter the ceramic substrate of the pyroelectric inductor at a temperature of 1000°C-1200°C for 6 hours.

[0057] Step 6: Sputter metal onto the surface of the U-shaped capacitor plate to form a silver electrode;

[0058] Step 7: Polarize the ceramic pyroelectric inductor at a polarization temperature of 135℃, a voltage of 1.5~6KV / mm, and a time of 5-10min.

[0059] Step 8: Fabricate the terminal electrodes of the inductor and weld the capacitor to the inductor support.

[0060] Step 9: Laser-cut ceramic plate, clean the surface of the sensor, and form a pyroelectric ceramic sensing unit chip;

[0061] Step 10: Solder the pyroelectric ceramic sensing element chip onto the circuit board, located at the very center of the circuit board.

[0062] Preferably, wherein:

[0063] The metal outer shell has a positioning end on the brim, which is located at the exact center of the metal base device's identification end;

[0064] The metal casing is welded and sealed in a closed environment, and the sensor is simultaneously filled with a protective inert gas (such as argon or nitrogen).

[0065] The metal casing is made of corrosion-resistant material to improve durability.

[0066] Preferably, wherein:

[0067] The circuit board is made of glass fiber or ceramic material with a thickness of 0.1-1.6mm, and connects power pins and signal pins;

[0068] The MOS transistor is located at the signal pin on the edge of the circuit board and is designed with low noise to improve signal amplification.

[0069] The circuit board is designed with a single or multiple layers to enhance electromagnetic compatibility and heat dissipation. Beneficial effects

[0070] In summary, due to the adoption of the above technical solutions, the capacitive PIR pyroelectric sensor of this utility model has the following advantages:

[0071] 1. High sensitivity: By optimizing the sensor structure and material selection, the reception efficiency of infrared signals has been significantly improved.

[0072] Second: Stable signal processing: Advanced signal amplification technology and anti-interference design are adopted to ensure the stability of signal processing.

[0073] Third: Reliable manufacturing process: Detailed manufacturing steps and parameter control ensure the high quality and consistency of the products.

[0074] 4. Durable packaging: The use of corrosion-resistant materials and inert gas sealing improves the durability and reliability of the sensor. Attached Figure Description

[0075] Figure 1 This is one of the overall structural schematic diagrams of the capacitive PIR pyroelectric sensor of this utility model.

[0076] Figure 2 This is the second schematic diagram of the overall structure of the capacitive PIR pyroelectric sensor of this utility model.

[0077] Figure 3 This is a schematic diagram of the power supply and signal pins of this utility model.

[0078] Figure 4 This is a schematic diagram of the position and structure of the metal shell filter of this utility model.

[0079] Figure 5 This is a schematic diagram of the structure of the astigmatic plate of the capacitive PIR pyroelectric sensor of this utility model.

[0080] Figure 6 This is a schematic diagram of the structure of the U-shaped infrared sensitive material of this utility model.

[0081] Figure 7 This is a schematic diagram of the internal structure of the capacitive PIR pyroelectric sensor of this utility model.

[0082] Figure 8 This is a schematic diagram of the sensing element capacitor structure of the capacitive PIR pyroelectric sensor of this utility model.

[0083] Figure 9 This invention relates to the sensor's packaging structure, signal processing circuit, and equivalent circuit diagram. Detailed Implementation

[0084] See Figures 1-8 This is a specific embodiment of a PIR pyroelectric sensor described in this application.

[0085] like Figures 1-8 As shown, the capacitive PIR pyroelectric sensor in this embodiment includes a metal housing 3, a metal housing brim positioning end 3-1, a metal housing top window 3-2; a metal base 2, a metal base identification end 2-1; power pins 1-1 and 1-3, circuit board pads 1-1-1 and 1-3-1; signal pin 1-2, circuit board pad 1-2-1; an infrared filter 10, an optical pass-through plate 9, a diffuser 8, a ceramic substrate 6, U-shaped infrared sensor capacitors 7-1 and 7-2, sensor support capacitors 5-1 and 5-2, a circuit board 4, and a MOSFET 11. The specific positions and connections of each component are as follows:

[0086] Metal casing 3: Used to protect internal components and provide electromagnetic shielding.

[0087] Metal base 2: Fixes the sensor and provides mechanical support.

[0088] Power supply pin and signal pin 1: used for input power and output signal, respectively.

[0089] Infrared filter 10: Installed at the top window of the metal casing, used to filter non-infrared light.

[0090] Diffuser 8: Located below the infrared filter, used to refract or reflect infrared signals.

[0091] Ceramic substrate 6: Supports U-shaped infrared sensitive material to form an infrared sensor capacitor.

[0092] Sensor support capacitors 5-1 and 5-2: support the infrared sensor capacitor and are electrically connected to it.

[0093] Circuit board 4: Integrated signal processing circuit, including MOSFET 11 and other necessary electronic components.

[0094] U-shaped infrared-sensitive material:

[0095] like Figure 5 As shown, a U-shaped infrared sensitive material is sintered on a ceramic substrate 6 to form an infrared sensor capacitor. The material width is 0.5mm to 2mm and the thickness is 0.05-0.15mm, optimized for best performance. The U-shaped structure helps increase the surface area of ​​the material, thereby enhancing infrared absorption. The sensor support capacitor connects to the U-shaped infrared capacitor plates at both ends of the ceramic substrate. The two support capacitors have the same capacitance. The symmetrical U-shaped infrared ceramic body and the support capacitor 5 form a new set of sensing capacitors 5-1U and 5-2U, making the reverse-connected capacitor plates asymmetrical to enhance the sensitivity of the sensing signal. The external infrared signal diffuser 8 refracts or reflects the infrared signal passing through the infrared filter onto the sensing capacitor plates. The power supply of the PIR pyroelectric sensor is input through power pin 1-1, and the infrared sensing signal is amplified by MOSFET 11 and output through intermediate signal pin 1-2.

[0096] Capacitive PIR pyroelectric sensor structural design:

[0097] 1. Metal casing 3 and base 2: The metal casing is made of corrosion-resistant material. An infrared filter and a diffuser are embedded in the top window and fixed and encapsulated in the sensor with black resin glue.

[0098] 2. Infrared filter 10: A coated monocrystalline silicon wafer is used to improve infrared transmittance.

[0099] 3. Astigmatism plate 8: The surface has a semi-circular groove, and the upper and lower plates are rotated 90° and combined together. The interior forms an interlaced wavy reflective surface in the horizontal and vertical directions, with a spacing of 0.1mm to 0.5mm.

[0100] 4. Ceramic substrate 6 and sensor capacitors 5-1U and 5-2U: U-shaped infrared sensitive material is printed on the ceramic substrate, and after sintering, it forms an infrared sensor with a finger-to-finger spacing of 0.2mm to 0.8mm.

[0101] 5. Sensor support capacitors 5-1 and 5-2: rectangular design with a recessed middle, and the electrodes at both ends are respectively connected to the infrared sensor capacitor plate and the auxiliary fixing end, and are welded to the ceramic substrate 6.

[0102] 6. Circuit Board and MOSFET 11: Circuit Board 4 is made of glass fiber or ceramic material with a thickness of 0.1-1.6mm, and connects power supply pins and signal pins; MOSFET is located at the signal pin on the edge of the circuit board and adopts a low noise design.

[0103] Infrared ceramic capacitor manufacturing method:

[0104] 1. Grind the pyroelectric inductor ceramic powder: filter with a 500-mesh steel mesh and prepare the inductor slurry.

[0105] 2. Fabrication of the internal electrode of the sensor: Print a conductive paste with a thickness of 0.5-12μm on a ceramic plate.

[0106] 3. Printing the underlying protective film: Printing the pyroelectric inductor underlying protective film on the ceramic and drying and curing it at 160°C.

[0107] 4. Printing pyroelectric inductor ceramic paste: forming U-shaped capacitor plates with a thickness of 0.05-0.15mm.

[0108] 5. Sintering ceramic substrate: Temperature 1000°C-1200°C, time 6 hours.

[0109] 6. Metal sputtering: forming silver electrodes on the surface of the U-shaped capacitor plates.

[0110] 7. Polarization treatment: polarization temperature 135℃, voltage 1.5~6KV / mm, time 5-10min.

[0111] 8. Welding electrodes: Fabricate the terminal electrodes of the inductor and weld the capacitor of the inductor support.

[0112] 9. Laser cutting and cleaning: Cutting ceramic plates and cleaning the surface of the sensor to form a pyroelectric ceramic sensing unit chip.

[0113] 10. Welding the chip: Weld the pyroelectric ceramic sensing element chip onto the circuit board, located in the center of the circuit board.

[0114] like Figure 4 , Figure 6 As shown, the infrared filter 10 and the diffuser 8 are located on the upper and lower sides of the light transmission plate 9, and are embedded in the top window of the metal shell 3. They are fixed by black resin glue and encapsulated in the metal shell of the sensor. The filter 10 is flush with the top surface of the metal shell 3. The black resin glue not only plays a fixing role, but also absorbs excess light and reduces interference.

[0115] The infrared filter 10 uses a coated monocrystalline silicon wafer. The choice of coated monocrystalline silicon wafer can significantly improve the transmittance of infrared light, thereby enhancing the sensitivity of the sensor. The fixing method ensures that the filter and diffuser will not shift or fall off during use, guaranteeing long-term stable working performance.

[0116] External infrared signals are directly or reflected onto the plates of sensing capacitors 5-1U and 5-2U through the filter 10 and the diffuser 8. The sensing signals are input to the circuit board through the support capacitors 5-1 and 5-2, and are amplified by the MOSFET 11 and output through the signal pin 1-2.

[0117] like Figure 5 As shown, the diffuser surface has semi-circular grooves, with two pieces offset by 90° and combined together, forming an alternating corrugated reflective surface in the horizontal and vertical directions inside. Changing the refraction angle of infrared light on the ceramic sensor capacitor improves the sensing sensitivity. The spacing of the corrugated reflective surfaces is 0.1mm to 0.5mm, which helps improve the reception efficiency of infrared signals.

[0118] The semi-circular groove and corrugated reflective surface design effectively disperse and reflect infrared light, increasing the sensor's ability to receive infrared light from different directions. Appropriate spacing optimizes the reflection effect, ensuring maximum signal reception. This composite structure enables the sensor to receive infrared signals from multiple angles, improving detection range and accuracy.

[0119] like Figure 8 As shown, the infrared sensor capacitor has a U-shaped symmetrical structure with its forks distributed at the center of the ceramic substrate 6, effectively receiving external incident signals. The two ends are connected in reverse to the capacitor supported by the sensor via bottom electrodes, canceling out interference signals caused by changes in ambient temperature. The fork spacing of the U-shaped symmetrical structure ranges from 0.2mm to 0.8mm. This U-shaped symmetrical structure and specific fork spacing design optimize capacitor performance, improving the sensor's response speed and sensitivity. The connection method of the bottom electrodes ensures good contact between the capacitor and the circuit, enhancing reliability. The symmetrical structure provides better mechanical support, reducing performance fluctuations caused by vibration or temperature changes.

[0120] like Figure 8 , Figure 7 As shown, a protective film is printed under the U-shaped symmetrical capacitor plates and sintered onto a ceramic substrate.

[0121] The protective film uses specific materials (such as silicon nitride or zirconium oxide) to improve durability and stability. The use of the protective film prevents the capacitor from being affected by the external environment, extending its service life. The selection of specific materials improves corrosion resistance and mechanical strength. The U-shaped symmetrical capacitor has a rectangular groove in the middle plate and semi-circular grooves in the middle of the two side plates. After polarization, each plate of the U-shaped symmetrical capacitor has a resistance of 160Ω, and the two ends are welded to the inductor support capacitor via metal electrodes. The specific plate structure design optimizes the electric field distribution and improves capacitor performance. The use of highly conductive metal electrodes ensures good electrical connection and reduces resistance.

[0122] like Figure 8 , Figure 7 As shown, the sensor support capacitor is rectangular with a recessed center. Its two electrodes are connected to the infrared sensor capacitor plate and the auxiliary fixing end, respectively, and are soldered onto the ceramic substrate 6. The electrodes connecting the sensor support capacitors 5-1 and 5-2 are made of highly conductive materials (such as copper or silver) to improve the reliability of the electrical connection. The rectangular structure and recessed center design allow for adjustment of the sensor plate area and resistance as needed, resulting in higher sensitivity and reliability. The selection of highly conductive materials ensures a low-resistance connection, improving the reliability of signal transmission, and the soldering process ensures a long-term stable electrical connection.

[0123] like Figure 8 , Figure 7 As shown, the sensor's power pin 1-1 and signal pin 1-2 are led out from under the metal base, arranged in a circular pattern, with a distance of 2.54mm from the center of the metal base. This circular pin arrangement simplifies installation and wiring, facilitating automated production. Gold plating effectively prevents pin corrosion, ensuring long-term reliable electrical connections. The standardized pin spacing (2.54mm) conforms to industry standards, facilitating compatibility with other devices.

[0124] The manufacturing method and steps of the capacitive PIR pyroelectric sensor of this utility model include:

[0125] Step 1: Grind the pyroelectric inductor ceramic powder, filter it with a 500-mesh steel screen, and prepare the inductor slurry;

[0126] Step 2: Print a conductive paste with a thickness of 0.5-12μm on a ceramic plate to fabricate the inductive body electrode;

[0127] Step 3: Print the pyroelectric inductor underlayer protective film on the ceramic and dry and cure at 160°C;

[0128] Step 4: Print a pyroelectric inductor ceramic paste with a thickness of 0.05-0.15mm on the bottom protective film to form a U-shaped capacitor plate;

[0129] Step 5: Sinter the ceramic substrate of the pyroelectric inductor at a temperature of 1000°C-1200°C for 6 hours.

[0130] Step 6: Sputter metal onto the surface of the U-shaped capacitor plate to form a silver electrode;

[0131] Step 7: Polarize the ceramic pyroelectric inductor at a polarization temperature of 135℃, a voltage of 1.5~6KV / mm, and a time of 5-10min.

[0132] Step 8: Fabricate the terminal electrodes of the inductor and weld the capacitor to the inductor support.

[0133] Step 9: Laser-cut ceramic plate, clean the surface of the sensor, and form a pyroelectric ceramic sensing unit chip;

[0134] Step 10: Solder the pyroelectric ceramic sensing element chip onto the circuit board, located at the very center of the circuit board.

[0135] like Figure 1 , Figure 2 As shown, the sensor's metal housing 3 has a positioning end 3-1 on its cap edge, located at the center of the metal base device identification end 2-1. The metal housing is welded and sealed in a closed environment, and the sensor is simultaneously filled with a protective inert gas (such as argon or nitrogen). The metal housing 3 is made of corrosion-resistant material to improve durability. The positioning end design facilitates installation and identification, ensuring the accuracy and consistency of the sensor during installation. Sealing and filling with inert gas prevent internal components from getting damp and oxidizing, extending service life. The choice of corrosion-resistant material improves the durability of the housing and adapts to various harsh environments.

[0136] like Figures 5-8 As shown, sensor circuit board 4 is made of glass fiber or ceramic material with a thickness of 0.1-1.6mm, connecting power supply pins and signal pins. MOSFET 11 is located at the signal pin on the edge of the circuit board, employing a low-noise design to improve signal amplification. The circuit board uses a single-layer or multi-layer design to enhance electromagnetic compatibility and heat dissipation. Selecting appropriate materials and thicknesses ensures the mechanical strength and electrical performance of the circuit board. Glass fiber or ceramic materials have good insulation and heat resistance. The low-noise design of the MOSFET improves signal amplification and reduces noise interference. The placement of MOSFET 11 facilitates wiring and heat dissipation. Single-layer or multi-layer designs can optimize electromagnetic compatibility and heat dissipation performance according to requirements, ensuring stable operation of the sensor in complex electromagnetic environments.

[0137] As can be seen from the above embodiments, the beneficial effects of this application are:

[0138] 1. High sensitivity: By optimizing the sensor structure and material selection, the reception efficiency of infrared signals has been significantly improved.

[0139] Second: Stable signal processing: Advanced signal amplification technology and anti-interference design are adopted to ensure the stability of signal processing.

[0140] Third: Reliable manufacturing process: Detailed manufacturing steps and parameter control ensure the high quality and consistency of the products.

[0141] 4. Durable packaging: The use of corrosion-resistant materials and inert gas sealing improves the durability and reliability of the sensor.

[0142] The foregoing description illustrates and describes several preferred embodiments of this application. However, as mentioned above, for those skilled in the art, the specific embodiments are merely exemplary descriptions of this utility model. Obviously, the specific implementation of this utility model is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of this utility model, or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of this utility model.

Claims

1. A capacitive PIR pyroelectric sensor, comprising a metal housing, a metal base, power pins, signal pins, an infrared filter, an optical passband, a diffuser, a ceramic substrate, an infrared sensor capacitor, a sensor support capacitor, a circuit board, and a MOSFET, characterized in that: The capacitor in the sensor support is provided with a rectangular ceramic substrate; The ceramic substrate is printed with a U-shaped infrared-sensitive material, which is sintered on the ceramic substrate to form an infrared sensor. The U-shaped infrared sensitive material has a width of 0.5mm to 2mm and a thickness of 0.05-0.15mm; The sensor support is capacitively connected to the U-shaped infrared capacitor electrode plate, located at both ends of the ceramic substrate. The infrared sensor and the support capacitor together form an asymmetric plate infrared sensor capacitor with capacities of 5-1U and 5-2U. The aforementioned diffuser will refract or reflect the infrared signal passed through the infrared filter onto the capacitor plate of the sensor. The power supply for the PIR pyroelectric sensor is input through the power supply pin, and the infrared sensing signal is amplified by a MOSFET and output through the intermediate signal pin.

2. The capacitive PIR pyroelectric sensor according to claim 1, characterized in that: The infrared filter and diffuser are located on the upper and lower sides of the optical pass card, embedded in the top window of the metal shell, fixed with black resin glue, and encapsulated inside the metal shell of the sensor. The infrared filter is made of coated monocrystalline silicon wafer to improve infrared transmittance.

3. The capacitive PIR pyroelectric sensor according to claim 1, characterized in that: The surface of the diffuser has a semi-circular groove, and the upper and lower pieces are deflected by 90° and combined together, forming an interlaced corrugated reflective surface in the horizontal and vertical directions inside. The spacing of the corrugated reflective surfaces is 0.1 mm to 0.5 mm, which helps to improve the reception efficiency of infrared signals.

4. The capacitive PIR pyroelectric sensor according to claim 1, characterized in that: The infrared sensor capacitor has a U-shaped symmetrical structure with forks distributed in the center of the ceramic substrate, and the two ends are connected to the sensor support capacitor through the bottom electrode. The interdigitation distance of the U-shaped symmetrical structure is 0.2 mm to 0.8 mm to optimize capacitor performance.

5. The capacitive PIR pyroelectric sensor according to claim 4, characterized in that: The U-shaped symmetrical capacitor body plates are printed with a protective film and sintered on a ceramic substrate. The U-shaped symmetrical capacitor has a rectangular groove in the middle plate and a semi-circular groove in the middle of the two side plates. After the U-shaped symmetrical capacitor plate is polarized, it is welded to the inductor support capacitor through metal electrodes at both ends. The protective film is made of silicon nitride or zirconium oxide to improve durability and stability.

6. The capacitive PIR pyroelectric sensor according to claim 1, characterized in that: The sensor support capacitor is rectangular with a concave center, and the electrodes at both ends are respectively connected to the infrared sensor capacitor plate and the auxiliary fixing end, and are welded to the ceramic substrate. The capacitor connection electrodes of the inductor support are made of copper or silver to improve the reliability of the electrical connection.

7. The capacitive PIR pyroelectric sensor according to claim 1, characterized in that: The power supply pins and signal pins are led out from under the metal base and arranged in a circular pattern. The distance from the pins to the center of the metal base is 2.54 mm. The pins are gold-plated to improve corrosion resistance and conductivity.

8. The capacitive PIR pyroelectric sensor according to claim 1, characterized in that: The metal outer shell has a positioning end on the brim, which is located at the exact center of the metal base device identification end; The metal casing is welded and sealed in a closed environment, and the sensor is simultaneously filled with protective inert gas argon or nitrogen. The metal casing is made of corrosion-resistant material to improve durability.

9. The capacitive PIR pyroelectric sensor according to claim 1, characterized in that: The circuit board is made of glass fiber or ceramic material with a thickness of 0.1-1.6mm, and connects power pins and signal pins; The MOS transistor is located at the signal pin on the edge of the circuit board and is designed with low noise to improve signal amplification. The circuit board is designed with a single or multiple layers to enhance electromagnetic compatibility and heat dissipation.

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