Infrared sensor structure and manufacturing process thereof

Abstract

The infrared sensor structure comprises a packaging shell, a potentiometer, a laser generator, a laser receiver, a comparator, an alarm and a chip, the potentiometer, the laser generator, the laser receiver, the comparator, the alarm and the chip are arranged in the packaging shell, the potentiometer comprises a volute frame and a carbon diaphragm arranged on the volute frame, and the two ends of the carbon diaphragm are each provided with a set of fixing ports; the packaging shell is provided with a variable measurement structure which adjusts the relative position of the contact piece and the carbon diaphragm according to the temperature change so as to change calibration parameters, and the base frame is provided with a variable resistance assembly which drives the co-location swing rod to deflect after the low-conductivity SMA and the high-conductivity SMA extend and deform. The variable resistance assembly is driven to adjust the positions of the contact piece and the carbon membrane, the reference voltage is changed in real time, it is ensured that when the temperature rises, the comparator can accurately adjust the reference voltage, the distance measuring precision is improved, and when the working temperature is abnormal, the alarm is triggered frequently or continuously to achieve the warning effect.

Description

Technical Field

[0001] The present invention relates to the technical field of infrared sensors, in particular to an infrared sensor structure and a manufacturing process thereof. Background Art

[0002] Infrared ranging sensor is a type of infrared sensor. Infrared sensors cover various sensor devices that use infrared spectra for detection and measurement. Infrared ranging sensors are specifically used to measure the distance between the target object and the sensor. Infrared ranging sensor transmits continuous infrared modulated signals. The phase difference between the received signal and the transmitted signal is used to calculate the distance. It achieves accurate distance measurement through a variety of working principles and is widely used in autonomous driving, drones, industrial automation and other fields.

[0003] A Chinese patent (publication number: CN117347977A) discloses an infrared ranging sensor control circuit. The solution specifically includes integrating a main control chip MCU, a power conversion chip, and an infrared ranging sensor module into a circuit board. The main control chip MCU is connected to the infrared ranging sensor module through an internal I2C pin, sends control instructions to the infrared ranging sensor module through the I2C interface and reads the register information of the infrared ranging sensor module, is connected to the 485 communication module through an internal 485 communication pin, and communicates with the host computer. The power conversion module supplies power to the main control chip MCU, the 485 communication module, and the infrared ranging sensor module. The infrared ranging sensor module can configure the target area to be measured into 4x4 areas, and perform real-time distance measurement on the target objects in the area. The light emitted is invisible infrared light, and real-time distance measurement is performed on the target objects in the area. The viewing angle is as wide as 63°. The entire circuit board is 20mm long and 20mm wide, saving space.

[0004] Infrared ranging sensors are usually based on the principle of reflective ranging. They measure distance by emitting infrared light and receiving reflected light. The signal processing circuit inside the sensor converts the received reflected light signal into an electrical signal and compares it with the preset trigger threshold. When the reflected signal reaches or exceeds the threshold, the sensor triggers the corresponding output (such as alarm, switch, etc.).

[0005] Among them, the increase in temperature usually leads to a decrease in the luminous efficiency of the infrared light source (such as an infrared LED or a laser diode), which means that under the same current, the intensity of the infrared light emitted by the infrared light source will weaken. The increase in temperature will also increase the dark current of the infrared receiver (such as a photodiode or a photoamplifier), that is, the current when there is no light, which will reduce the signal-to-noise ratio, increase the system noise, and affect the accuracy of the received signal. Furthermore, when the temperature rises, the luminous intensity of the infrared light source weakens and the dark current of the infrared receiver increases, which may cause the intensity of the reflected infrared signal to decrease. Due to the decrease in the strength of the received signal, the infrared sensor needs a closer target object to generate a strong enough reflection signal to reach or exceed the set trigger threshold.

[0006] Therefore, in actual use, temperature factors will affect the measurement accuracy of the infrared ranging sensor. Specifically, the trigger distance of the infrared ranging sensor will be closer than the set distance to trigger the corresponding action. Although the existing infrared sensor uses a temperature compensation algorithm to reduce the impact of temperature changes to a certain extent, the temperature compensation effect is still limited in an environment with a large temperature difference. Large temperature differences will still have a significant adverse effect on the measurement accuracy. Furthermore, an infrared sensor structure and a manufacturing process thereof are proposed. Summary of the invention

[0007] The purpose of the present invention is to provide an infrared sensor structure and a manufacturing process thereof, which have the advantages of accurately adjusting the reference voltage when the temperature rises and improving the ranging accuracy, thereby solving the problem that large temperature differences have a significant adverse effect on the measurement accuracy.

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an infrared sensor structure, including a packaging shell and a potentiometer, a laser generator, a laser receiver, a comparator, an alarm and a chip arranged therein, the potentiometer including a volute frame and a carbon diaphragm arranged thereon, a group of fixed ports are respectively arranged at both ends of the carbon diaphragm, the volute frame is provided with a contact piece that is in sliding contact with the carbon diaphragm and a sliding port that is electrically connected to the contact piece, the packaging shell is provided with a variable measurement structure that adjusts the relative position of the contact piece and the carbon diaphragm according to temperature changes to change the calibration parameters; The variable measurement structure includes a co-located pendulum rod that rotates on a fixed axis on a volute frame and is coaxially fixed with the contact piece, a base frame that is fixedly connected to the packaging shell is provided on one side of the volute frame, a low-conductivity SMA and a high-conductivity SMA that deform at different step temperatures are provided on the base frame, and a variable resistance component that drives the co-located pendulum rod to deflect after the low-conductivity SMA and the high-conductivity SMA are stretched and deformed is provided on the base frame; A polyurethane gasket is filled between the potentiometer and the packaging shell, and the shape and size of the polyurethane gasket are consistent with the contact surface between the potentiometer and the fixing bracket.

[0009] Preferably, a polytetrafluoroethylene pad is filled between the comparator and the chip, and the polytetrafluoroethylene pad covers the interface between the comparator and the chip.

[0010] Preferably, silicone O-rings are clamped and fixed on the interface rings corresponding to the outer shell of both the laser generator and the laser receiver, and the optical windows of the laser generator and the laser receiver are coated.

[0011] Preferably, a bypass capacitor is provided on one side of the comparator, the bypass capacitor is fixedly arranged on the snail frame and close to the power pin in the comparator, and the bypass capacitor is grounded; A current limiting resistor is electrically connected between the comparator and the alarm, one end of the current limiting resistor is electrically connected to the output end of the comparator, and the other end is electrically connected to the positive electrode of the alarm; The laser receiver is electrically connected to a pull-up resistor, and the laser generator is electrically connected to a current-limiting resistor.

[0012] Preferably, the variable resistance assembly comprises a transverse hollow cylinder arranged on a base frame and driven by the deformation of a low-conductivity SMA and a high-conductivity SMA, the base frame is provided with a main direction cavity for sliding connection of the transverse hollow cylinder, a transverse column is slidably penetrated through the transverse hollow cylinder, a conical ring is fixedly connected to the transverse column, and a pressure relief spring is sleeved on the outer circumference of the transverse column, and the two ends of the pressure relief spring are respectively fixedly connected to the transverse hollow cylinder and the conical ring; One end of the horizontal column away from the horizontal hollow cylinder slides through the base frame and is fixedly connected with a positioning pin, and a positioning groove for the positioning pin to slide and connect is provided on the same position swing rod; The base frame is provided with a limiting component for limiting the movement of the transverse column.

[0013] Preferably, the limit assembly includes a connecting cavity opened on the base frame and communicating with the main cavity, a blocking column is slidably connected in the connecting cavity, the blocking column includes an integrally formed right-angled edge and a beveled edge, the beveled edge is in sliding contact with the conical surface of the conical ring, a yield spring is fixedly connected below the blocking column, and one end of the yield spring away from the blocking column is fixedly connected to the base frame.

[0014] Preferably, a cam is fixedly sleeved on the transverse hollow cylinder, a side of the cam facing the oblique slide groove is fixedly connected with a downward extension column, and a secondary cavity for sliding connection of the downward extension column and communicating with the connecting cavity is opened on the base frame; The side of the lower extension column facing the oblique slide groove is provided with an integrally formed end inclined surface, and the oblique slide groove is provided with an oblique slide groove in sliding contact with the end inclined surface; A return spring is sleeved on the outer circumference of the transverse hollow cylinder, and two ends of the return spring are respectively fixedly connected to the cam and the base frame.

[0015] Preferably, the base frame is provided with a middle block and a slot body for sliding connection of the middle block, the two ends of the low-conductivity SMA are respectively fixedly connected to the middle block and the cam, and the two ends of the high-conductivity SMA are respectively fixedly connected to the middle block and the base frame; A stopper is arranged on one side of the middle block away from the cam, and the stopper is fixedly connected to the base frame.

[0016] A manufacturing process of an infrared sensor structure, applied to an infrared sensor structure, comprises the following steps: S1. Optical window coating: Anti-reflection coating is applied on the optical window surface of laser receiver and laser transmitter, and a uniform silicon dioxide film is formed by chemical vapor deposition method; S2. Electrical insulation coating: Clean the chip surface, use trimethylaluminum and ammonia as precursors, deposit aluminum nitride coating layer by layer in the reaction chamber, and form a uniform and dense aluminum nitride film on the chip surface; S3, Shell protection seal: Use spraying method to evenly spray polyurethane coating on the outer surface of the packaging shell to provide mechanical protection and anti-corrosion performance; A layer of aluminum conductive coating is deposited on the surface of the polyurethane coating by magnetron sputtering to achieve electromagnetic shielding performance; The silicone coating is evenly covered on the inner surface of the packaging shell by dipping, providing moisture-proof and waterproof properties.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention sets a variable measurement structure, utilizes the automatic deformation of low-conductivity SMA and high-conductivity SMA according to temperature changes, drives the variable resistance component to adjust the position of the contact piece and the carbon diaphragm, and changes the reference voltage in real time, ensuring that when the temperature rises, the comparator can accurately adjust the reference voltage, improve the ranging accuracy, and achieve a warning effect by frequently or continuously triggering the alarm at abnormal operating temperature.

[0018] 2. The present invention can filter out high-frequency noise and stabilize the power supply voltage by setting a bypass capacitor, and protect the laser diode through a current-limiting resistor to prevent overcurrent damage, thereby ensuring stable output of the laser signal. At the same time, through a pull-up resistor, it is ensured that the laser receiver maintains a high level when there is no signal, thereby enhancing the accuracy of signal detection.

[0019] 3. The present invention effectively protects the internal components of the sensor from the invasion of moisture, dust and other pollutants by providing a polyurethane gasket, a silicone O-ring and a polytetrafluoroethylene gasket, thereby improving the reliability of the sensor in harsh environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of a circuit in which a comparator of the present invention is located; Figure 2 This is a schematic diagram of the components where the horizontal column of the present invention is located; Figure 3 For the present invention Figure 2 Enlarged view of point A in the middle; Figure 4 For the present invention Figure 2 Enlarged view of point B in the middle; Figure 5 It is a schematic diagram of the base frame and its internal parts of the present invention; Figure 6 This is a schematic diagram of the components where the co-located pendulum rod of the present invention is located; Figure 7 For the present invention Figure 6 Enlarged view of point C in the middle; Figure 8 This is a schematic diagram of the circuit where the laser generator and the current limiting resistor of the present invention are located; Fig. 9 This is a schematic diagram of the circuit where the laser receiver and the pull-up resistor of the present invention are located; Fig.10 The figure is a schematic diagram of the manufacturing process of an infrared sensor structure of the present invention.

[0021] In the figure: 1. Snail frame; 2. Contact piece; 3. Carbon diaphragm; 4. Base frame; 5. Low-conductivity SMA; 6. Middle block; 7. High-conductivity SMA; 8. Stop block; 9. Cam; 10. Transverse hollow cylinder; 11. Return spring; 12. Transverse column; 13. Pressure release spring; 14. Conical ring; 15. Lower extension column; 16. Main cavity; 17. Secondary cavity; 18. Connecting cavity; 19. Blocking column; 191. Right-angled side; 192. Beveled side; 20. Oblique slide groove; 21. Give way spring; 22. Locating pin; 23. Same-position rocker rod; 24. Locating groove. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] See also Figures 1 to 10The present invention provides a technical solution: an infrared sensor structure, including a packaging shell and a potentiometer, a laser generator, a laser receiver, a comparator, an alarm and a chip arranged therein, the potentiometer includes a volute frame 1 and a carbon diaphragm 3 arranged thereon, a group of fixed ends are respectively arranged at both ends of the carbon diaphragm 3, the volute frame 1 is provided with a contact piece 2 in sliding contact with the carbon diaphragm 3 and a sliding end electrically connected to the contact piece 2, the packaging shell is provided with a variable measurement structure for adjusting the relative position of the contact piece 2 and the carbon diaphragm 3 according to temperature changes to change the calibration parameters; The variable measurement structure includes a co-located pendulum 23 which rotates on a fixed axis on a volute frame 1 and is coaxially fixed with the contact piece 2. A base frame 4 which is fixedly connected to the packaging shell is provided on one side of the volute frame 1. A low-conductivity SMA5 and a high-conductivity SMA7 which deform at different step temperatures are provided on the base frame 4. A variable resistance component which drives the co-located pendulum 23 to deflect after the low-conductivity SMA5 and the high-conductivity SMA7 are stretched and deformed is provided on the base frame 4. A polyurethane gasket is filled between the potentiometer and the packaging shell, and the shape and size of the polyurethane gasket are consistent with the contact surface between the potentiometer and the fixing bracket.

[0024] like Figure 1 , Figure 2 , Figure 8 and Fig. 9 As shown, the two ends of the laser generator and the laser receiver are respectively connected to the positive pole (VCC) and the negative pole (GND) of the power supply, and the potentiometer includes two groups of fixed ports, one group of fixed ports is electrically connected to the positive pole (VCC) of the power supply, and the other group of fixed ports is electrically connected to the negative pole (GND) of the power supply, and the sliding port is electrically connected to the non-inverting input end of the comparator, the sliding end C (Port C) outputs a reference voltage (V_ref), the inverting input end of the comparator is electrically connected to the laser receiver, and the comparator receives the signal voltage (V_sensor) and the reference voltage (V_ref) from the laser receiver to determine whether to trigger the alarm.

[0025] Among them, when the temperature rises, the luminous efficiency of the laser transmitter will decrease, which means that under the same current, the intensity of the infrared light emitted by the infrared light source will weaken. The temperature increase will increase the dark current of the laser receiver (such as a photodiode or a photoelectric amplifier), that is, the current when there is no light, which will reduce the signal-to-noise ratio, increase system noise, and affect the accuracy of the received signal. Furthermore, when the temperature rises, the luminous intensity of the laser transmitter is weakened and the dark current of the laser receiver increases, which may cause the intensity of the reflected infrared signal to decrease. Due to the decrease in the intensity of the received signal, a closer target object is required to generate a sufficiently strong reflected signal. Therefore, in order to ensure the measurement accuracy and to ensure that the alarm is triggered at the set distance position, when the temperature rises, the variable resistance component can be driven to operate through the deformation of the low-conductivity SMA5 and the high-conductivity SMA7 to change the relative position of the contact piece 2 on the carbon film 3, thereby changing the reference voltage (V_ref). When affected by factors such as the weakening of the luminous intensity of the laser transmitter and the increase of the dark current of the laser receiver, the alarm can still be triggered at the set distance threshold.

[0026] Among them, by arranging a polyurethane gasket between the potentiometer and the packaging shell, the potentiometer can be provided with effective waterproof and dustproof protection, and at the same time, it can be ensured that the rotation process of the contact piece 2 in the potentiometer under the action of external force is not hindered.

[0027] At the same time, it should be noted that a temperature compensation algorithm can also be set in the chip. When the temperature rises significantly, the automatic response of the variable measurement structure can be used to ensure the measurement accuracy by mechanical adjustment, such as seasonal temperature changes. When the temperature change range is small, such as temperature changes caused by light factors, the temperature compensation algorithm is used to adjust the ranging data based on the set reference temperature. If the low-conductivity SMA5 and the high-conductivity SMA7 have already undergone elongation and deformation when the temperature rises, the temperature compensation algorithm can update the reference temperature value, and then output the corrected ranging value based on the current correction value.

[0028] In one of the more preferred embodiments, a polytetrafluoroethylene pad is filled between the comparator and the chip, and the polytetrafluoroethylene pad covers the interface between the comparator and the chip.

[0029] Silicone O-type sealing rings are clamped and fixed on the interface rings corresponding to the outer shell of the laser generator and the laser receiver, and the optical windows of the laser generator and the laser receiver are coated.

[0030] The polytetrafluoroethylene gasket is cut into appropriate sizes and covered to the interface between the comparator and the chip, so that the polytetrafluoroethylene gasket fits tightly to the contact surface. The polytetrafluoroethylene gasket not only provides efficient electrical insulation, but also prevents moisture and dust from entering the interface between the comparator and the chip, thereby ensuring the stability of the circuit.

[0031] At the same time, when installing the laser generator and laser receiver, clean the contact surfaces of the laser generator, laser receiver and packaging shell to ensure that there are no pollutants, evenly place the silicone O-ring on the interface ring of the laser generator or laser receiver to cover the entire connection area, use screws or pressing mechanisms to apply uniform pressure to install the laser generator or laser receiver, ensure that the sealing ring is in close contact with the interface surface, and check the pressing of the silicone O-ring to ensure that there is no distortion or bubbles, and the laser path is not affected. The silicone O-ring provides efficient waterproof and dustproof protection, while allowing slight thermal expansion of the laser generator during operation to avoid damage caused by stress concentration.

[0032] Furthermore, a bypass capacitor is provided on one side of the comparator, the bypass capacitor is fixedly arranged on the snail frame 1 and is close to the power supply pin in the comparator, and the bypass capacitor is grounded; A current limiting resistor is electrically connected between the comparator and the alarm, one end of the current limiting resistor is electrically connected to the output end of the comparator, and the other end is electrically connected to the positive electrode of the alarm; The laser receiver is electrically connected to a pull-up resistor, and the laser generator is electrically connected to a current-limiting resistor.

[0033] like Figure 1 , Figure 8 and Fig. 9 As shown, the bypass capacitor (C1) is usually connected between the power supply (Vcc) and the ground (GND), close to the power pins of the components that require a stable power supply, such as Figure 1 As shown, the bypass capacitor (C1) is close to the power pin in the comparator. When there is high-frequency noise or transient changes in the power supply voltage in the circuit, the bypass capacitor (C1) can quickly charge and discharge, smooth the power supply voltage, and reduce the impact of these noises and fluctuations on sensitive components. Among them, high-frequency noise will propagate on the power line and affect the circuit performance. The bypass capacitor, as a low-impedance high-frequency path, can guide these high-frequency noises to the ground, thereby purifying the power supply voltage. During the operation of the circuit, the comparator may suddenly require a large current. The bypass capacitor (C1) can quickly release the stored charge to meet this instantaneous current demand and avoid an instantaneous drop in the power supply voltage.

[0034] At the same time, the current limiting resistor (R_L) is connected between the positive pole of the power supply (Vcc) and the laser generator. Its main purpose is to limit the current passing through the laser diode in the laser generator to ensure that the laser diode operates within a safe operating current range. The laser diode is a semiconductor device that can emit high-intensity lasers. In order to ensure its normal operation, the current passing through it must be controlled, because excessive current will cause the laser diode to overheat, degrade in performance, or even permanently damaged. Therefore, by connecting a current limiting resistor (R_L) in series in front of the laser diode, the current flowing through the laser diode can be effectively controlled to ensure that it operates within a safe range, thereby preventing it from overheating or damage. By stabilizing the current, it is ensured that the laser diode emits a stable and consistent laser signal, which helps to improve the accuracy of ranging.

[0035] At the same time, a pull-up resistor (R_pull-up) is electrically connected to the laser receiver. The pull-up resistor (R_pull-up) ensures that the signal voltage (V_sensor) remains at a high level (close to Vcc) when the laser receiver does not receive a laser signal. When a laser signal is received, the signal voltage (V_sensor) changes due to signal changes.

[0036] Further, the variable resistance assembly includes a transverse hollow cylinder 10 arranged on the base frame 4 and driven by the deformation of the low-conductivity SMA5 and the high-conductivity SMA7, the base frame 4 is provided with a main direction cavity 16 for sliding connection of the transverse hollow cylinder 10, a transverse column 12 is slidably penetrated on the transverse hollow cylinder 10, a conical ring 14 is fixedly connected to the transverse column 12, and a pressure relief spring 13 is sleeved on the outer peripheral surface of the transverse column 12, and the two ends of the pressure relief spring 13 are respectively fixedly connected to the transverse hollow cylinder 10 and the conical ring 14; The end of the horizontal column 12 away from the horizontal hollow cylinder 10 slides through the base frame 4 and is fixedly connected with a positioning pin 22, and a positioning groove 24 for the positioning pin 22 to slide and connect is formed on the same position swing rod 23; The base frame 4 is provided with a limiting assembly for limiting the movement of the transverse column 12 .

[0037] The limiting assembly includes a connecting cavity 18 which is opened on the base frame 4 and communicates with the main direction cavity 16. A blocking column 19 is slidably connected in the connecting cavity 18. The blocking column 19 includes an integrally formed right-angled edge 191 and a beveled edge 192. The beveled edge 192 is in sliding contact with the conical surface of the conical ring 14. A yield spring 21 is fixedly connected below the blocking column 19. One end of the yield spring 21 away from the blocking column 19 is fixedly connected to the base frame 4.

[0038] The lateral hollow cylinder 10 is fixedly sleeved with a cam 9, and a side of the cam 9 facing the oblique slide groove 20 is fixedly connected with a down-extending column 15, and a secondary cavity 17 for sliding connection of the down-extending column 15 and communicating with the connecting cavity 18 is opened on the base frame 4; The side of the lower extension column 15 facing the oblique slide groove 20 is provided with an integrally formed end inclined surface, and the oblique slide groove 20 is provided with an oblique slide groove 20 that is in sliding contact with the end inclined surface; A return spring 11 is sleeved on the outer circumference of the transverse hollow cylinder 10 , and two ends of the return spring 11 are fixedly connected to the cam 9 and the base frame 4 respectively.

[0039] The base frame 4 is provided with a center block 6 and a slot body for sliding connection of the center block 6. The two ends of the low-conductivity SMA 5 are respectively fixedly connected to the center block 6 and the cam 9, and the two ends of the high-conductivity SMA 7 are respectively fixedly connected to the center block 6 and the base frame 4. A stopper 8 is provided on the side of the middle block 6 away from the cam 9 , and the stopper 8 is fixedly connected to the base frame 4 .

[0040] like Figure 2-Figure 7 As shown, the temperature value required for the deformation of the high-conductivity SMA7 is higher than the temperature value required for the deformation of the low-conductivity SMA5. When the temperature rises to the deformation temperature of the low-conductivity SMA5, the low-conductivity SMA5 undergoes elongation deformation, wherein the two ends of the low-conductivity SMA5 are respectively fixed on the middle block 6 and the cam 9, and the middle block 6 is abutted against the stopper 8. Therefore, when the low-conductivity SMA5 is deformed, the cam 9 can be driven to move away from the side of the high-conductivity SMA7.

[0041] At the same time, under the action of the elastic potential energy of the pressure release spring 13, as the cam 9 drives the transverse hollow cylinder 10 to move toward the side of the co-positioned rocker rod 23, at this time, the conical ring 14 gradually approaches the side of the blocking column 19 until the conical ring 14 and the blocking column 19 integrally formed on the blocking column 19 collide with each other. At the same time, when the cam 9 is running horizontally, it can synchronously drive the lower extension column 15 fixed thereon to slide in the secondary cavity 17, thereby driving the lower extension column 15 to gradually approach the side of the inclined slide groove 20.

[0042] When the conical ring 14 collides with the right-angled side 191, the conical ring 14 cannot continue to follow the movement of the cam 9 under the restriction of the blocking column 19, and then the pressure release spring 13 is compressed and deformed with the horizontal movement of the cam 9 and the horizontal hollow cylinder 10. When the low-conductivity SMA5 is elongated to cause the horizontal column 12 to move in the horizontal direction, the horizontal position of the positioning pin 22 fixed at the end of the horizontal column 12 changes, thereby driving the positioning pin 22 to slide on the positioning groove 24, and driving the co-positioned swing rod 23 to swing. The relative positions of the contact piece 2 and the carbon diaphragm 3 are changed synchronously, wherein when the relative position of the contact piece 2 on the carbon diaphragm 3 changes, the resistance value between the fixed port and the sliding port changes. Combined with the above, when the temperature rises, the strength of the received signal decreases, and a closer target object is required to generate a sufficiently strong reflected signal; therefore, by changing the resistance value between the fixed port and the sliding port, the reference voltage (V_ref) is changed, so that the alarm can still be triggered after the signal voltage (V_sensor) strength decreases.

[0043] It should be noted that, in the actual process, the deformation temperature value of the low-conductivity SMA5 and the swing distance of the contact piece 2 on the carbon film 3 due to the deformation of the low-conductivity SMA5 need to be adapted to the fluctuation of the signal voltage (V_sensor) affected by the temperature change and the resistance value of the potentiometer used, so as to ensure that when the contact piece 2 swings due to the elongation deformation of the low-conductivity SMA5, the reference voltage (V_ref) can be adjusted within a reasonable range, thereby ensuring the measurement accuracy.

[0044] At the same time, if the temperature continues to rise to the temperature value at which the high-conductivity SMA 7 can be deformed, it means that the operating temperature of the infrared sensor exceeds its set operating temperature. After the high-conductivity SMA 7 is elongated and deformed, it can push the middle block 6 to drive the horizontal hollow cylinder 10 to move horizontally again, so that the pressure release spring 13 continues to be compressed. At this time, the lower extension column 15 can continue to move horizontally with the cam 9 until the end inclined surface of the lower extension column 15 integrally formed contacts the inclined slide groove 20 and is in the lower When the extension column 15 slides on the oblique slide groove 20, it can squeeze the oblique slide groove 20 and drive the yield spring 21 to undergo compression deformation, so as to cause the oblique slide groove 20 to retract into the connecting cavity 18. At this time, the right-angled edge 191 is disengaged from the conical ring 14, and the conical ring 14 is no longer restricted by the right-angled edge 191. The pressure release spring 13 restores its deformation and drives the horizontal column 12 to move rapidly toward the direction of the co-positioned rocker 23, thereby causing the co-positioned rocker 23 to deflect again to change the relative position between the contact piece 2 and the carbon diaphragm 3.

[0045] Among them, the further deflection of the co-location pendulum 23 can change the reference voltage (V_ref) and reduce the value of the changed reference voltage (V_ref). At this time, when the distance between the target object and the infrared sensor is greater than the set distance, its signal voltage (V_sensor) is greater than the reference voltage (V_ref), thereby triggering the alarm. Through the secondary deflection of the co-location pendulum 23, the value of the signal voltage (V_sensor) is smaller, thereby frequently or continuously triggering the alarm to achieve the purpose of early warning of abnormal working temperature.

[0046] At the same time, when the temperature is lower than the deformation temperature of the low-conductivity SMA5, the transverse hollow cylinder 10 and the cam 9 return to their initial positions. At this time, the conical ring 14 is squeezed into contact with the bevel edge 192, and under the squeezing of the conical ring 14, the blocking column 19 can be retracted into the connecting cavity 18 by the deformation of the yield spring 21, so that the setting of the blocking column 19 will not cause motion interference to the resetting process of the parts.

[0047] A manufacturing process of an infrared sensor structure, applied to an infrared sensor structure, comprises the following steps: S1. Optical window coating: Anti-reflection coating is applied on the optical window surface of laser receiver and laser transmitter, and a uniform silicon dioxide film is formed by chemical vapor deposition method; S2. Electrical insulation coating: Clean the chip surface, use trimethylaluminum and ammonia as precursors, deposit aluminum nitride coating layer by layer in the reaction chamber, and form a uniform and dense aluminum nitride film on the chip surface; S3, Shell protection seal: Use spraying method to evenly spray polyurethane coating on the outer surface of the packaging shell to provide mechanical protection and anti-corrosion performance; A layer of aluminum conductive coating is deposited on the surface of the polyurethane coating by magnetron sputtering to achieve electromagnetic shielding performance; The silicone coating is evenly covered on the inner surface of the packaging shell by dipping, providing moisture-proof and waterproof properties.

[0048] like Fig.10 As shown, in S1, the silicon dioxide film applied on the optical window surface of the laser receiver and the laser transmitter can improve the optical performance of the laser receiver and the laser transmitter, so as to significantly reduce the reflectivity of light on the window surface, improve the transmittance of the laser signal, and reduce the light loss. At the same time, the silicon dioxide film can effectively prevent harmful substances such as dust, moisture, and chemicals from adhering to the surface of the optical window, keep the optical window clean and transparent, and provide a hard protective layer to enhance the wear resistance of the optical window and reduce scratches and wear in daily use.

[0049] In S2, trimethylaluminum and ammonia are used as precursors to deposit aluminum nitride coating layer by layer in the reaction chamber to form a uniform and dense aluminum nitride film. The aluminum nitride film coating provides excellent electrical insulation and thermal conductivity to prevent electrical interference between the chip and the packaging shell. At the same time, the aluminum nitride film can effectively dissipate heat and maintain a stable operating temperature of the chip.

[0050] In S3, the coating sequence of the packaging protective shell from the inside to the outside is silicone coating-metal conductive coating-polyurethane coating. The polyurethane coating provides solid external protection, the metal conductive coating effectively shields electromagnetic interference, and the inner silicone coating blocks moisture and water. The synergistic effect of multiple layers of coating ensures the reliability and stability of the sensor in various complex environments.

[0051] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An infrared sensor structure, comprising a packaging shell and a potentiometer, a laser generator, a laser receiver, a comparator, an alarm and a chip arranged therein, the potentiometer comprising a volute frame (1) and a carbon diaphragm (3) arranged thereon, a group of fixed ports being respectively arranged at both ends of the carbon diaphragm (3), the volute frame (1) being provided with a contact piece (2) in sliding contact with the carbon diaphragm (3) and a sliding port being electrically connected to the contact piece (2), characterized in that: The packaging shell is provided with a variable measurement structure for adjusting the relative position of the contact sheet (2) and the carbon membrane sheet (3) according to temperature changes, thereby changing the calibration parameters; The variable measurement structure comprises a co-located pendulum rod (23) which rotates on a fixed axis on a volute frame (1) and is coaxially fixed with the contact piece (2); a base frame (4) which is fixedly connected to the packaging shell is provided on one side of the volute frame (1); a low-conductivity SMA (5) and a high-conductivity SMA (7) which deform at different step temperatures are provided on the base frame (4); and a variable resistance component which drives the co-located pendulum rod (23) to deflect after the low-conductivity SMA (5) and the high-conductivity SMA (7) are stretched and deformed. A polyurethane gasket is filled between the potentiometer and the packaging shell, and the shape and size of the polyurethane gasket are consistent with the contact surface between the potentiometer and the fixing bracket.

2. An infrared sensor structure according to claim 1, characterized in that: A polytetrafluoroethylene pad is filled between the comparator and the chip, and the polytetrafluoroethylene pad covers the interface between the comparator and the chip.

3. An infrared sensor structure according to claim 2, characterized in that: Silicone O-type sealing rings are clamped and fixed on the interface rings corresponding to the outer shell of the laser generator and the laser receiver, and the optical windows of the laser generator and the laser receiver are coated.

4. An infrared sensor structure according to claim 3, characterized in that: A bypass capacitor is provided on one side of the comparator, the bypass capacitor is fixedly arranged on the snail frame (1) and is close to the power supply pin in the comparator, and the bypass capacitor is grounded; A current limiting resistor is electrically connected between the comparator and the alarm, one end of the current limiting resistor is electrically connected to the output end of the comparator, and the other end is electrically connected to the positive electrode of the alarm; The laser receiver is electrically connected to a pull-up resistor, and the laser generator is electrically connected to a current-limiting resistor.

5. An infrared sensor structure according to claim 4, characterized in that: The variable resistance assembly comprises a transverse hollow cylinder (10) arranged on a base frame (4) and driven by the deformation of a low-conductivity SMA (5) and a high-conductivity SMA (7); a main direction cavity (16) is provided on the base frame (4) for the transverse hollow cylinder (10) to be slidably connected; a transverse column (12) is slidably penetrated through the transverse hollow cylinder (10); a conical ring (14) is fixedly connected to the transverse column (12); a pressure release spring (13) is sleeved on the outer peripheral surface of the transverse column (12); and two ends of the pressure release spring (13) are respectively fixedly connected to the transverse hollow cylinder (10) and the conical ring (14); One end of the transverse column (12) away from the transverse hollow cylinder (10) slides through the base frame (4) and is fixedly connected with a positioning pin (22), and a positioning groove (24) for sliding connection of the positioning pin (22) is formed on the same position swing rod (23); The base frame (4) is provided with a limiting component for limiting the movement of the transverse column (12).

6. An infrared sensor structure according to claim 5, characterized in that: The limit assembly comprises a connecting cavity (18) which is opened on the base frame (4) and communicates with the main cavity (16); a blocking column (19) is slidably connected in the connecting cavity (18); the blocking column (19) comprises an integrally formed right-angled edge (191) and an oblique angled edge (192); the oblique angled edge (192) is in sliding contact with a conical surface of the conical ring (14); a yielding spring (21) is fixedly connected below the blocking column (19); and one end of the yielding spring (21) away from the blocking column (19) is fixedly connected to the base frame (4).

7. An infrared sensor structure according to claim 6, characterized in that: A cam (9) is fixedly sleeved on the transverse hollow cylinder (10), a side of the cam (9) facing the oblique slide groove (20) is fixedly connected to a downward extension column (15), and a secondary cavity (17) for sliding connection of the downward extension column (15) and communicating with the connecting cavity (18) is formed on the base frame (4); An integrally formed end bevel is provided on one side of the lower extension column (15) facing the oblique slide groove (20), and an oblique slide groove (20) is provided on the oblique slide groove (20) for sliding contact with the end bevel; A return spring (11) is sleeved on the outer circumference of the transverse hollow cylinder (10), and two ends of the return spring (11) are respectively fixedly connected to the cam (9) and the base frame (4).

8. An infrared sensor structure according to claim 7, characterized in that: The base frame (4) is provided with a middle block (6) and a slot body for sliding connection of the middle block (6), the two ends of the low-conductivity SMA (5) are respectively fixedly connected to the middle block (6) and the cam (9), and the two ends of the high-conductivity SMA (7) are respectively fixedly connected to the middle block (6) and the base frame (4); A stopper (8) is provided on the side of the middle block (6) away from the cam (9), and the stopper (8) is fixedly connected to the base frame (4).

9. A manufacturing process of an infrared sensor structure, applied to an infrared sensor structure as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Optical window coating: Anti-reflection coating is applied on the optical window surface of laser receiver and laser transmitter, and a uniform silicon dioxide film is formed by chemical vapor deposition method; S2. Electrical insulation coating: Clean the chip surface, use trimethylaluminum and ammonia as precursors, deposit aluminum nitride coating layer by layer in the reaction chamber, and form a uniform and dense aluminum nitride film on the chip surface; S3, Shell protection seal: Use spraying method to evenly spray polyurethane coating on the outer surface of the packaging shell to provide mechanical protection and anti-corrosion performance; A layer of aluminum conductive coating is deposited on the surface of the polyurethane coating by magnetron sputtering to achieve electromagnetic shielding performance; The silicone coating is evenly covered on the inner surface of the packaging shell by dipping, providing moisture-proof and waterproof properties.

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