Infrared sensor structure and manufacturing process thereof

Abstract

The application discloses an infrared sensor structure and a manufacturing process thereof, which comprises a packaging shell and a chip, a potentiometer, a laser generator, a laser receiver, a comparator and an alarm arranged in the packaging shell. The potentiometer comprises a snail-shaped frame and a carbon diaphragm arranged on the snail-shaped frame. A group of fixed ports are arranged at two ends of the carbon diaphragm. A variable measurement structure for adjusting the relative position of a contact and the carbon diaphragm according to temperature change and changing calibration parameters is arranged on the packaging shell. A variable resistance assembly for driving a same-position swing lever to deflect after the low-conductivity SMA and high-conductivity SMA are elongated and deformed is arranged on the base frame. The variable measurement structure is arranged, the low-conductivity SMA and the high-conductivity SMA are automatically deformed according to temperature change, the variable resistance assembly is driven to adjust the position of the contact and the carbon diaphragm, the reference voltage is changed in real time, the comparator can accurately adjust the reference voltage when the temperature rises, the ranging precision is improved, and the alarm is frequently or continuously triggered to achieve the warning effect when the working temperature is abnormal.

Description

TECHNICAL FIELD

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

[0002] Infrared distance sensor is a kind of infrared sensor, infrared sensor covers various sensor devices that use infrared spectrum for detection and measurement, while infrared distance sensor is specially used for measuring the distance between target object and sensor, infrared distance sensor transmits continuous infrared modulated signal, and the phase difference between received signal and transmitted signal is used for calculating distance, which realizes accurate distance measurement through various working principles, and is widely used in automatic driving, unmanned aerial vehicle, industrial automation and other fields.

[0003] Chinese patent (announcement number: CN117347977A) discloses an infrared distance sensor control circuit, which specifically includes integrating main control chip MCU, power conversion chip and infrared distance sensor module on one circuit board, the main control chip MCU is connected with the infrared distance sensor module through internal I2C pin, sends control instruction to the infrared distance sensor module through I2C interface and reads register information of the infrared distance sensor module, is connected with 485 communication module through internal 485 communication pin, and communicates with host computer, the power conversion module supplies power for the main control chip MCU, 485 communication module and infrared distance sensor module, the infrared distance sensor module can configure the measured target area as 4x4 areas, and measure the distance of target object in the area in real time, the emitted light is invisible infrared light, and the distance of target object in the area is measured in real time, the viewing angle is up to 63°, the volume of the whole circuit board is 20mm long and 20mm wide, and space is saved.

[0004] Infrared distance sensor is usually based on reflection distance measurement principle, which measures distance by emitting infrared light and receiving reflected light, the signal processing circuit inside the sensor converts the received reflected light signal into electric signal, and compares it with the preset trigger threshold value, when the reflected signal reaches or exceeds the threshold value, the sensor triggers corresponding output (such as alarm, switch, etc.).

[0005] Wherein, the temperature rise usually causes the light emitting efficiency of the infrared light source (such as infrared LED or laser diode) to decrease, which means that the infrared light intensity emitted by the infrared light source will weaken under the same current, and the temperature rise also increases the dark current of the infrared receiver (such as photodiode or photoelectric amplifier), that is, the current in the absence of light, which reduces the signal-to-noise ratio, increases the system noise, and affects the accuracy of the received signal, and then, when the temperature rises, the light intensity of the infrared light source decreases and the dark current of the infrared receiver increases, which may cause the reflected infrared signal intensity to decrease, and due to the decrease in the received signal intensity, the infrared sensor needs a closer target object to produce a strong enough reflected signal to reach or exceed the set trigger threshold.

[0006] Therefore, in actual use, the temperature factor will affect the measurement accuracy of the infrared distance sensor, specifically, the trigger distance of the infrared distance 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 influence of temperature change to a certain extent, but in the environment with large temperature difference, the temperature compensation effect is still limited, and the large temperature difference change still has a significant adverse effect on the measurement accuracy, and then, an infrared sensor structure and its manufacturing process are proposed. SUMMARY

[0007] The purpose of the present application is to provide an infrared sensor structure and its manufacturing process, which has the advantages of accurately adjusting the reference voltage when the temperature rises and improving the distance measurement accuracy, and solves the problem of significant adverse effect of large temperature difference change on measurement accuracy.

[0008] To achieve the above purpose, the present application provides the following technical scheme: 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 in the packaging shell, the potentiometer comprising a snail-shaped frame and a carbon film sheet arranged thereon, one end of the carbon film sheet is provided with a group of fixed ports, the snail-shaped frame is provided with a contact piece in sliding contact with the carbon film sheet and a sliding port electrically connected with the contact piece, and the packaging shell is provided with a variable measurement structure for adjusting the relative position of the contact piece and the carbon film sheet according to the temperature change and changing the calibration parameter.

[0009] The variable measurement structure comprises a homopolar swing rod fixed coaxially between the contact piece and the snail-shaped frame and rotating on the snail-shaped frame, one side of the snail-shaped frame is provided with a base frame fixedly connected with the packaging shell, the base frame is provided with a low-conductivity SMA and a high-conductivity SMA which are deformed at different step temperatures, and the base frame is provided with a variable resistance assembly for driving the homopolar swing rod to deflect after the low-conductivity SMA and the high-conductivity SMA are elongated and deformed.

[0010] The potentiometer and the packaging shell are filled with polyurethane pads, and the shape and size of the polyurethane pads are consistent with the contact surface between the potentiometer and the fixed support.

[0011] Preferably, the comparator and the chip are filled with a polytetrafluoroethylene pad, and the polytetrafluoroethylene pad covers the interface between the comparator and the chip.

[0012] Preferably, the laser generator and the laser receiver are both clamped and fixed with a silica gel O-shaped sealing ring on the corresponding interface ring of the outer shell, and the optical windows of the laser generator and the laser receiver are both subjected to coating treatment.

[0013] Preferably, the comparator is provided with a bypass capacitor on one side, the bypass capacitor is fixedly arranged on the snail-shaped frame and close to the power supply pin in the comparator, and the bypass capacitor is arranged in ground connection;

[0014] The comparator is electrically connected with a current limiting resistor, 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;

[0015] The laser receiver is electrically connected with a pull-up resistor, and the laser generator is electrically connected with a current limiting resistor.

[0016] Preferably, the variable resistance assembly comprises a transverse hollow cylinder driven by a low-conductivity SMA and a high-conductivity SMA shape deformation variable and arranged on a base frame, the base frame is provided with a main cavity for sliding connection of the transverse hollow cylinder, a transverse column is slidingly penetrated through the transverse hollow cylinder, a conical ring is fixedly connected to the transverse column, a pressure relief spring is sleeved on the outer circumferential surface of the transverse column, and both ends of the pressure relief spring are fixedly connected to the transverse hollow cylinder and the conical ring respectively;

[0017] One end of the transverse column away from the transverse hollow cylinder is slidingly penetrated through the base frame and fixedly connected with a positioning pin, and the positioning pin is slidingly connected with a positioning groove arranged on the same-position swing rod.

[0018] The base frame is provided with a limiting assembly for limiting the movement of the transverse column.

[0019] Preferably, the limiting assembly comprises a linking cavity penetrating through the main cavity and arranged on the base frame, and a blocking column slidingly connected in the linking cavity, the blocking column comprises an integral right-angle edge and an integral bevel edge, the bevel edge is in sliding contact with the conical surface of the conical ring, and a blocking spring is fixedly connected below the blocking column, and one end of the blocking spring away from the blocking column is fixedly connected to the base frame.

[0020] Preferably, a cam is fixedly sleeved on the transverse hollow cylinder, a downward extending column is fixedly connected to one side of the cam facing the oblique sliding groove, and a secondary cavity penetrating through the linking cavity is arranged on the base frame and slidingly connected with the downward extending column;

[0021] One side of the downward extending column facing the oblique sliding groove is provided with an integral end bevel surface, and an oblique sliding groove in sliding contact with the end bevel surface is arranged on the oblique sliding groove;

[0022] The outer circumferential surface of the transverse hollow cylinder is sleeved with a reset spring, and two ends of the reset spring are fixedly connected to the cam and the base frame respectively.

[0023] Preferably, the base frame is provided with a median block and is provided with a groove one for sliding connection of the median block, two ends of the low-conductivity SMA are fixedly connected to the median block and the cam respectively, and two ends of the high-conductivity SMA are fixedly connected to the median block and the base frame respectively.

[0024] The side of the median block away from the cam is provided with a stop block, and the stop block is fixedly connected to the base frame.

[0025] A manufacturing process of an infrared sensor structure, applied to an infrared sensor structure, comprising the following steps:

[0026] S1, optical window coating: the optical window surface of the laser receiver and the laser transmitter is applied with an anti-reflection coating, a uniform silicon dioxide film is formed by a chemical vapor deposition method;

[0027] S2, electrically insulating coating: the chip surface is cleaned, trimethylaluminum and ammonia gas are used as precursors, an aluminum nitride coating is deposited layer by layer in a reaction chamber, and a uniform and dense aluminum nitride film is formed on the chip surface;

[0028] S3, shell protection and sealing: polyurethane paint is uniformly sprayed on the outer surface of the packaging shell by spraying, mechanical protection and corrosion resistance are provided;

[0029] An aluminum conductive coating is deposited on the surface of the polyurethane coating by a magnetron sputtering method, and electromagnetic shielding performance is realized;

[0030] Silica paint is uniformly coated on the inner surface of the packaging shell by dipping, moisture and water resistance are provided.

[0031] Compared with the prior art, the beneficial effects of the present application are as follows:

[0032] 1、The present application sets up a variable measurement structure, uses the automatic deformation of low-conductivity SMA and high-conductivity SMA according to temperature changes to drive the variable resistance assembly to adjust the position of the contact piece and the carbon film piece, and changes the reference voltage in real time, so that the comparator can accurately adjust the reference voltage when the temperature rises, the measurement accuracy is improved, and when the working temperature is abnormal, the alarm is triggered frequently or continuously to achieve the warning effect.

[0033] 2、The present application sets up a bypass capacitor, which can filter out high-frequency noise, stabilize the power supply voltage, and protect the laser diode through a current limiting resistor to prevent overcurrent damage and ensure stable output of the laser signal, and through the pull-up resistor, the laser receiver maintains a high level when there is no signal, enhancing the accuracy of signal detection.

[0034] 3、The polyurethane gasket, silica gel O-shaped sealing ring and polytetrafluoroethylene gasket effectively prevent the internal elements of the sensor from being invaded by moisture, dust and other pollutants, and improve the reliability of the sensor in harsh environments. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The schematic diagram of the circuit where the comparator of the present application is located;

[0036] Figure 2 The schematic diagram of the component where the transverse column of the present application is located;

[0037] Figure 3 The schematic diagram of the present application Figure 2 The enlarged view of A in the present application;

[0038] Figure 4 The enlarged view of B in the present application Figure 2

[0039] Figure 5 The schematic diagram of the base frame and its internal components of the present application;

[0040] Figure 6 The schematic diagram of the component where the same-position swing rod of the present application is located;

[0041] Figure 7 The enlarged view of C in the present application Figure 6

[0042] Figure 8 The schematic diagram of the circuit where the laser generator and current limiting resistor of the present application are located;

[0043] Figure 9 The schematic diagram of the circuit where the laser receiver and pull-up resistor of the present application are located;

[0044] Figure 10 The manufacturing process schematic diagram of the infrared sensor structure of the present application.

[0045] In the figure: 1, volute frame; 2, contact piece; 3, carbon film piece; 4, base frame; 5, low-conductivity SMA; 6, middle block; 7, high-conductivity SMA; 8, stop block; 9, cam; 10, transverse hollow cylinder; 11, reset spring; 12, transverse column; 13, pressure relief spring; 14, conical ring; 15, lower extension column; 16, main direction cavity; 17, secondary direction cavity; 18, connection cavity; 19, blocking column; 191, right-angle side; 192, bevel side; 20, oblique sliding groove; 21, let-go spring; 22, positioning pin; 23, same-position swing rod; 24, positioning groove. DETAILED DESCRIPTION

[0046] ​​With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0047] Please refer to Figures 1 to 10 , the present application provides a technical solution: 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 in the packaging shell, the potentiometer comprising a volute frame 1 and a carbon film sheet 3 arranged on the volute frame 1, the carbon film sheet 3 having a group of fixed ends at both ends respectively, the volute frame 1 being provided with a contact piece 2 in sliding contact with the carbon film sheet 3 and a sliding end electrically connected with the contact piece 2, the packaging shell being provided with a variable measurement structure for adjusting the relative position of the contact piece 2 and the carbon film sheet 3 according to temperature change and changing the calibration parameter;

[0048] The variable measurement structure comprises a homopolar swing rod 23 fixed coaxially between the volute frame 1 and the contact piece 2, the volute frame 1 being provided with a base frame 4 fixedly connected with the packaging shell, the base frame 4 being provided with a low-conductivity SMA 5 and a high-conductivity SMA 7 deformed at different step temperatures, and the base frame 4 being provided with a variable resistance assembly for driving the homopolar swing rod 23 to deflect after the low-conductivity SMA 5 and the high-conductivity SMA 7 are elongated and deformed;

[0049] The potentiometer and the packaging shell are filled with a polyurethane gasket, the shape and size of the polyurethane gasket being consistent with the contact surface between the potentiometer and the fixed support.

[0050] As Figure 1 , Figure 2 , Figure 8 and Figure 9 shown, the two ends of the laser generator and the laser receiver are respectively connected with a positive electrode (VCC) and a negative electrode (GND) of a power supply, the potentiometer comprises two groups of fixed ports, one group of fixed ports is electrically connected with the positive electrode (VCC) of the power supply, the other group of fixed ports is electrically connected with the negative electrode (GND) of the power supply, and the sliding port is electrically connected with a non-inverting input end of the comparator, a sliding end C (Port C) outputs a reference voltage (V_ref), an inverting input end of the comparator is electrically connected with the laser receiver, the comparator receives a signal voltage (V_sensor) from the laser receiver and the reference voltage (V_ref) to determine whether to trigger the alarm.

[0051] When the temperature rises, the light emitting efficiency of the laser emitter will decrease, which means that the infrared light intensity emitted by the infrared light source will weaken under the same current. The increase in temperature will increase the dark current of the laser receiver (such as a photodiode or a photoelectric amplifier), which is the current when there is no light. This will reduce the signal-to-noise ratio, increase system noise, and affect the accuracy of the received signal. When the temperature rises, the light intensity of the laser emitter decreases and the dark current of the laser receiver increases, which may cause the reflected infrared signal intensity to decrease. Since the received signal intensity decreases, a closer target object is needed to produce a strong enough reflected signal. Therefore, to ensure measurement accuracy and ensure that the alarm is triggered at the set distance, the low-conductivity SMA5 and high-conductivity SMA7 can be deformed to drive the variable resistance component to operate, thereby changing the relative position of the contact piece 2 on the carbon film 3, and thus changing the reference voltage (V_ref). Even when the light intensity of the laser emitter decreases and the dark current of the laser receiver increases, the alarm can still be triggered at the set distance threshold.

[0052] By providing a polyurethane gasket between the potentiometer and the packaging shell, the potentiometer can be effectively protected from water and dust, and the rotation of the contact piece 2 in the potentiometer under external force can be ensured without being hindered.

[0053] At the same time, it should be noted that a temperature compensation algorithm can also be provided in the chip. When the temperature rises significantly, the variable measurement structure responds automatically to ensure measurement accuracy through 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 adjusts the distance measurement data based on the reference temperature set. If the low-conductivity SMA5 and high-conductivity SMA7 have elongated and deformed when the temperature rises, the temperature compensation algorithm can update the reference temperature value, and then output the corrected distance measurement value based on the current correction value.

[0054] In a more preferred embodiment, the comparator and the chip are filled with a polytetrafluoroethylene pad that covers the interface between the comparator and the chip.

[0055] The laser generator and the laser receiver are both fixed with a silicone O-ring on the corresponding interface ring of the outer shell, and the optical windows of the laser generator and the laser receiver are both coated.

[0056] The polytetrafluoroethylene gasket is cut to the appropriate size and covers the interface between the comparator and the chip, ensuring that the polytetrafluoroethylene gasket tightly fits 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.

[0057] At the same time, when installing the laser generator and the laser receiver, clean the contact surfaces of the laser generator, the laser receiver and the packaging shell, ensure that there is no contamination, place the silica gel O-shaped sealing ring uniformly on the interface ring of the laser generator or the laser receiver, cover the entire connection area, apply uniform pressure to the installed laser generator or laser receiver using screws or press-fitting mechanisms, ensure that the sealing ring is in close contact with the interface surface, and check the press-fitting of the silica gel O-shaped sealing ring to ensure that there is no distortion, bubbles, and the laser path is not affected. The silica gel O-shaped sealing ring provides efficient waterproof and dustproof protection, while allowing the laser generator to expand slightly when working, avoiding damage caused by stress concentration.

[0058] Further, the comparator is provided with a bypass capacitor on one side, and the bypass capacitor is fixedly arranged on the snail-shaped frame 1 and close to the power supply pin in the comparator, and the bypass capacitor is grounded;

[0059] The 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;

[0060] The laser receiver is electrically connected with a pull-up resistor, and the laser generator is electrically connected with a current limiting resistor.

[0061] As shown in Figure 1 , Figure 8 and Figure 9 , the bypass capacitor (C1) is usually connected between the power supply (Vcc) and the ground (GND), close to the power supply pin of the element that needs to be stabilized, as shown in Figure 1 , the bypass capacitor (C1) is close to the power supply pin in the comparator, when there is high-frequency noise or power supply voltage transient change in the circuit, the bypass capacitor (C1) can quickly charge and discharge, smooth the power supply voltage, reduce the influence of these noises and fluctuations on sensitive elements, wherein high-frequency noise can propagate on the power supply line, affecting the performance of the circuit, 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, and the bypass capacitor (C1) can quickly release the stored charge to meet this instantaneous current demand, avoiding the instantaneous drop of the power supply voltage.

[0062] Meanwhile, a current limiting resistor (R_L) is connected between the positive pole of the power supply (Vcc) and the laser generator, and its main purpose is to limit the current through the laser diode in the laser generator, to ensure that the laser diode operates within a safe operating current range, wherein the laser diode is a semiconductor device capable of emitting high-intensity laser, in order to ensure its normal operation, the current through it must be controlled, because excessive current will cause the laser diode to overheat, performance degradation or even permanent damage, therefore, by connecting a current limiting resistor (R_L) in series with 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 being damaged, and by stabilizing the current, it ensures that the laser diode emits stable and consistent laser signals, which helps to improve the accuracy of distance measurement.

[0063] Meanwhile, the laser receiver is electrically connected with a pull-up resistor (R_pull-up), which 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, and changes when a laser signal is received.

[0064] Further, the variable resistance assembly comprises a transverse hollow cylinder 10 arranged on the base frame 4 and driven by low-conductivity SMA 5 and high-conductivity SMA 7 shape variable, 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 slidingly penetrated on the transverse hollow cylinder 10, a conical ring 14 is fixedly connected on the transverse column 12, and a pressure relief spring 13 is sleeved on the outer circumferential surface of the transverse column 12, both ends of the pressure relief spring 13 are fixedly connected on the transverse hollow cylinder 10 and the conical ring 14 respectively;

[0065] The end of the transverse column 12 away from the transverse hollow cylinder 10 slidingly penetrates the base frame 4 and is fixedly connected with a positioning pin 22, and a positioning slot 24 is formed in the same position swing rod 23 for sliding connection of the positioning pin 22;

[0066] The base frame 4 is provided with a limiting assembly for limiting the movement of the transverse column 12.

[0067] The limiting assembly comprises a connection cavity 18 formed in the base frame 4 and penetrating between the main direction cavity 16, a blocking column 19 is slidingly connected in the connection cavity 18, the blocking column 19 comprises an integral straight edge 191 and an inclined edge 192, the inclined edge 192 is in sliding contact with the conical surface of the conical ring 14, and a yielding spring 21 is fixedly connected below the blocking column 19, and the end of the yielding spring 21 away from the blocking column 19 is fixedly connected on the base frame 4.

[0068] The transverse hollow cylinder 10 is fixedly sleeved with a cam 9, the cam 9 is fixedly connected with a lower column 15 on one side of the oblique sliding groove 20, the base frame 4 is provided with a secondary cavity 17 for sliding connection of the lower column 15 and in communication with the connecting cavity 18;

[0069] The lower column 15 is provided with an integral end bevel on one side of the oblique sliding groove 20, and the oblique sliding groove 20 is provided with an oblique sliding groove 20 in sliding contact with the end bevel;

[0070] The outer periphery of the transverse hollow cylinder 10 is sleeved with a reset spring 11, and the two ends of the reset spring 11 are fixedly connected to the cam 9 and the base frame 4 respectively.

[0071] The base frame 4 is provided with a middle block 6 and is provided with a groove one for sliding connection of the middle block 6, the two ends of the low-conductivity SMA 5 are fixedly connected to the middle block 6 and the cam 9 respectively, and the two ends of the high-conductivity SMA 7 are fixedly connected to the middle block 6 and the base frame 4 respectively;

[0072] The side of the middle block 6 away from the cam 9 is provided with a stop block 8, and the stop block 8 is fixedly connected to the base frame 4.

[0073] As shown in Figures 2-7 The temperature value required for deformation of the high-conductivity SMA 7 is higher than that of the low-conductivity SMA 5, when the temperature rises to the deformation temperature of the low-conductivity SMA 5, the low-conductivity SMA 5 occurs elongation deformation, wherein the two ends of the low-conductivity SMA 5 are fixedly arranged on the middle block 6 and the cam 9 respectively, and the middle block 6 is in abutting connection with the stop block 8, therefore when the low-conductivity SMA 5 deforms, the cam 9 can be driven to move away from the side of the high-conductivity SMA 7.

[0074] At the same time, under the action of the elastic potential energy of the pressure relief spring 13, the transverse hollow cylinder 10 moves towards the side of the same position swing lever 23 driven by the cam 9, at this time, the conical ring 14 gradually approaches the side of the blocking column 19 until the conical ring 14 abuts against the blocking column 19 integrally formed on the blocking column 19, at the same time, the cam 9 can drive the lower column 15 fixedly arranged thereon to slide in the secondary cavity 17 when running horizontally, thereby driving the lower column 15 to gradually approach the side of the oblique sliding groove 20.

[0075] Among them, when the conical ring 14 conflicts with the right-angled side 191, under the restriction of the blocking column 19, the conical ring 14 cannot continue to follow the movement of the cam 9, and then with the horizontal movement of the cam 9 and the horizontal hollow cylinder 10, the pressure relief spring 13 is compressed and deformed. Among them, 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 same-position rocker 23 to swing. The relative positions of the contact piece 2 and the carbon diaphragm 3 are changed synchronously. When the relative position of the contact piece 2 on the carbon diaphragm 3 changes, the resistance value between its fixed port and the sliding port changes. Combined with the above proposal: when the temperature rises, the received signal strength 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.

[0076] It should be noted that, in actual practice, the deformation temperature of the low-conductivity SMA5 and the swing distance of the contact piece 2 on the carbon diaphragm 3 due to the deformation of the low-conductivity SMA5 need to be compatible with the fluctuation of the signal voltage (V_sensor) caused by temperature changes and the resistance value of the potentiometer used, 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 measurement accuracy.

[0077] At the same time, if the temperature continues to rise to the temperature value at which the high-conductivity SMA7 can be deformed, it means that the operating temperature of the infrared sensor exceeds its set operating temperature. After the high-conductivity SMA7 is stretched and deformed, it can push the center block 6 to drive the horizontal hollow cylinder 10 to move horizontally again, thereby causing the pressure relief spring 13 to continue to be compressed. At this time, the lower extension column 15 can continue to move horizontally following the cam 9 until the end inclined surface of the lower extension column 15 integrally formed contacts the inclined slide groove 20 and is lowered. When the extension column 15 slides on the oblique slide groove 20, it can squeeze the oblique slide groove 20 and drive the give way spring 21 to undergo compression deformation, so as to prompt 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 recovers its deformation and drives the horizontal column 12 to move rapidly toward the direction of the parallel rocker 23, thereby causing the parallel rocker 23 to deflect again to change the relative position between the contact piece 2 and the carbon diaphragm 3.

[0078] Among them, the further deflection of the parity 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. Moreover, through the secondary deflection of the parity pendulum 23, the value of the signal voltage (V_sensor) is reduced, thereby frequently or continuously triggering the alarm to achieve the purpose of early warning of abnormal working temperature.

[0079] 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 with the resetting process of the parts.

[0080] A manufacturing process for an infrared sensor structure, applied to an infrared sensor structure, comprises the following steps:

[0081] S1. Optical window coating: Anti-reflection coating is applied to the optical window surface of the laser receiver and laser transmitter by chemical vapor deposition method to form a uniform silicon dioxide film;

[0082] S2. Electrical insulation coating: Clean the chip surface, use trimethylaluminum and ammonia as precursors, and deposit aluminum nitride coating layer by layer in the reaction chamber to form a uniform and dense aluminum nitride film on the chip surface;

[0083] 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;

[0084] A layer of aluminum conductive coating is deposited on the surface of the polyurethane coating by magnetron sputtering to achieve electromagnetic shielding performance;

[0085] The silicone coating is evenly covered on the inner surface of the packaging shell by dipping, providing moisture-proof and waterproof performance.

[0086] like Figure 10 As shown in S1, the silicon dioxide film applied to 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 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, keeping the optical window clean and transparent, and providing a hard protective layer to enhance the wear resistance of the optical window and reduce scratches and wear during daily use.

[0087] In S2, using trimethylaluminum and ammonia as precursors, an aluminum nitride coating is deposited layer by layer in the reaction chamber to form a uniform and dense aluminum nitride film, which provides excellent electrical insulation and thermal conductivity, prevents electrical interference between the chip and the package shell, and effectively dissipates heat to maintain the stable working temperature of the chip.

[0088] In S3, the coating sequence of the package protective shell from inside to outside is silica gel coating-metal conductive coating-polyurethane coating, wherein the polyurethane coating provides firm external protection, the metal conductive coating effectively shields electromagnetic interference, and the inner layer of silica gel coating blocks moisture and water, and through the synergistic effect of the multi-layer coating, the reliability and stability of the sensor in various complex environments are ensured.

[0089] Although embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An infrared sensor structure, comprising a package housing and a potentiometer, a laser generator, a laser receiver, a comparator, an alarm, and a chip arranged therein, wherein the potentiometer comprises a volute frame (1) and a carbon diaphragm (3) arranged thereon, wherein a group of fixed ports are respectively provided at both ends of the carbon diaphragm (3), and the volute frame (1) is provided with a contact (2) that is in sliding contact with the carbon diaphragm (3) and a sliding port that is electrically connected to the contact (2), characterized in that: 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, thereby changing the calibration parameters; The variable measurement structure comprises a co-located pendulum (23) which rotates on a fixed axis on a volute frame (1) and is co-axially fixed with a contact piece (2); a base frame (4) which is fixedly connected to a 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 (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; 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; The variable resistance component 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) for sliding connection of the transverse hollow cylinder (10) is provided on the base frame (4); a transverse column (12) is slidably passed through 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 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 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 provided 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); The limiting assembly includes a connecting cavity (18) provided on the base frame (4) and communicating 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 side (191) and an oblique angled side (192); the oblique angled side (192) is in sliding contact with the 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); A cam (9) is fixedly sleeved on the transverse hollow cylinder (10), a lower extension column (15) is fixedly connected to the side of the cam (9) facing the oblique slide groove (20), and a secondary cavity (17) for sliding connection of the lower extension column (15) and communicating with the connecting cavity (18) is formed on the base frame (4); The lower extension column (15) is provided with an integrally formed end bevel on one side facing the oblique slide groove (20), and the oblique slide groove (20) is provided with an oblique slide groove (20) in sliding contact with the end bevel; The outer circumference of the transverse hollow cylinder (10) is sleeved with a return spring (11), and the two ends of the return spring (11) are fixedly connected to the cam (9) and the base frame (4) respectively; 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); 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 center block (6) away from the cam (9), and the stopper (8) is fixedly connected to the base frame (4); By setting up a variable measurement structure and utilizing the automatic deformation of low-conductivity SMA and high-conductivity SMA according to temperature changes, the variable resistor component is driven to adjust the position of the contact piece and the carbon diaphragm, and the reference voltage is changed in real time. This ensures 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 when the operating temperature is abnormal.

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

Images