Lung function instrument capable of resisting ambient light interference

Abstract

The utility model provides a lung function instrument capable of resisting ambient light interference. A microprocessor outputs a PWM (Pulse Width Modulation) control signal. And the infrared emission module generates and emits infrared light with preset frequency fluctuation based on the PWM control signal. The turbine assembly rotates under the action of gas exhaled by the subject, and the infrared light with the preset frequency fluctuation is discontinuously blocked. The infrared receiving module generates an output level signal, and the output level signal is a first level under the condition that infrared light fluctuating at a preset frequency is received; under the condition that the constant infrared light is received or the infrared light is not received, the output level signal is a second level; the first level is opposite to the second level. And the microprocessor receives the output level signal and determines a lung function detection result according to the output level signal. The device can effectively distinguish infrared signals emitted by the device from infrared signals in ambient light, so that lung function parameters can still be accurately measured under strong ambient light.

Description

Technical Field

[0001] This utility model relates to the field of circuit technology, and in particular to a pulmonary function instrument that is resistant to ambient light interference. Background Technology

[0002] A pulmonary function testing device is a widely used medical device in hospitals, clinics, and homes, capable of accurately measuring various parameters of lung function. During the test, the air exhaled by the subject passes through a turbine inside the device, transforming it into a rotating airflow that drives a blade to rotate. An infrared transmitting and receiving module inside the device is aligned with the rotating blade. As the blade rotates, the light received by the receiving module is blocked by the blade, generating intermittent infrared signals. These signals change synchronously with the blade's rotation and are generated corresponding signals in the receiving module. After processing by the signal processing circuit, these signals are converted into square wave signals synchronized with the blade's rotation. Finally, the microprocessor further processes these signals to generate several major parameters for pulmonary function measurement, including volume, flow rate, and time.

[0003] Because pulmonary function meters use infrared light for measurement, excessive ambient light, such as fluorescent lamps, dual ruby ​​lamps, infrared heaters, and direct sunlight, can cause inaccurate measurements or even malfunction. Therefore, this device has strict environmental requirements and is particularly unsuitable for outdoor use, causing considerable inconvenience and limitations for users. Utility Model Content

[0004] This invention provides a pulmonary function analyzer resistant to ambient light interference, aiming to solve the technical problem that existing pulmonary function analyzers cannot function properly under strong ambient light. This invention can effectively distinguish between its own emitted infrared signals and infrared signals in ambient light, thus enabling accurate measurement of pulmonary function parameters even under strong ambient light. This broadens the application scenarios of the pulmonary function analyzer and improves its ease of use and reliability.

[0005] This invention provides a pulmonary function instrument resistant to ambient light interference, comprising: a microprocessor for outputting a PWM control signal; an infrared emitting module electrically connected to the microprocessor for generating and emitting infrared light with a preset frequency fluctuation based on the PWM control signal; a turbine assembly for rotating under the action of the subject's exhaled air to intermittently block the infrared light with the preset frequency fluctuation; and an infrared receiving module, wherein the infrared emitting module and the infrared receiving module are respectively disposed on both sides of the turbine assembly; the infrared receiving module is electrically connected to the microprocessor and is used to generate an output level signal, wherein when the infrared light with the preset frequency fluctuation is received, the output level signal is a first level; when the infrared light with the preset frequency fluctuation is not received, the output level is a second level; the first level and the second level are opposite; the microprocessor is also used to receive the output level signal and determine the pulmonary function test result based on the output level signal.

[0006] According to the present invention, a pulmonary function instrument resistant to ambient light interference is provided, wherein the infrared emitting module includes an infrared emitting tube, a MOS transistor, a first resistor, and a second resistor; the first end of the first resistor is electrically connected to a power supply, the second end of the first resistor is electrically connected to the anode of the infrared emitting tube, the cathode of the infrared emitting tube is electrically connected to the drain of the MOS transistor, the gate of the MOS transistor is electrically connected to the first end of the second resistor, and the source of the MOS transistor and the second end of the second resistor are both grounded.

[0007] According to the present invention, a pulmonary function instrument resistant to ambient light interference is provided, wherein the turbine assembly includes a turbine and turbine blades.

[0008] According to the present invention, a pulmonary function instrument resistant to ambient light interference is provided, wherein the infrared receiving module includes an infrared receiving head, a capacitor, a third resistor, and a fourth resistor; the first end of the third resistor and the second end of the fourth resistor are both electrically connected to a power supply, the second end of the third resistor is electrically connected to the first end of the infrared receiving head and the first end of the capacitor, the second end of the fourth resistor is electrically connected to the second end of the infrared receiving head, and the third end of the infrared receiving head and the second end of the capacitor are both grounded.

[0009] According to the present invention, a pulmonary function instrument resistant to ambient light interference is provided, wherein the infrared receiver head includes: a photodiode for converting received infrared light into a current signal; a gain amplifier electrically connected to the photodiode for amplifying the current signal output by the photodiode; a filter electrically connected to the gain amplifier for filtering the amplified signal output by the gain amplifier, filtering out signals corresponding to constant ambient infrared light, and outputting signals corresponding to infrared light fluctuating at a preset frequency; a demodulator electrically connected to the filter for demodulating the signals corresponding to infrared light fluctuating at the preset frequency and outputting a square wave signal; and a gain controller electrically connected to the gain amplifier for dynamically adjusting the gain of the gain amplifier through a closed-loop feedback mechanism.

[0010] According to the present invention, a pulmonary function instrument resistant to ambient light interference is provided, wherein the infrared emitting module emits infrared light with a frequency range of 10~100kHz and a wavelength range of 750~2500nm.

[0011] According to the present invention, a pulmonary function instrument resistant to ambient light interference is provided, wherein the number of infrared emitting modules and infrared receiving modules is one pair or more pairs.

[0012] According to the present invention, a lung function instrument resistant to ambient light interference is provided, wherein the infrared emitting module and the infrared receiving module are arranged at preset angle intervals around the turbine assembly, and the same pair of infrared emitting modules and infrared receiving modules are symmetrically arranged relative to the turbine assembly.

[0013] According to the present invention, a lung function instrument resistant to ambient light interference is provided, wherein the microprocessor is also used to monitor the transmission frequency of the infrared emitting module and the receiving frequency of the infrared receiving module in real time, and automatically adjust the PWM control signal when a frequency deviation is detected.

[0014] According to the present invention, a lung function instrument resistant to ambient light interference is provided. The lung function instrument further includes a housing with a sealing structure to prevent ambient light from directly entering the optical path of the infrared emitting module and the infrared receiving module.

[0015] This invention provides a pulmonary function instrument resistant to ambient light interference, comprising a microprocessor, an infrared emitting module, a turbine assembly, and an infrared receiving module. The microprocessor outputs a PWM control signal. Based on the PWM control signal, the infrared emitting module generates and emits infrared light with a preset frequency fluctuation. The turbine assembly rotates under the action of the subject's exhaled air, intermittently blocking the infrared light with the preset frequency fluctuation. The infrared receiving module generates an output level signal, and when receiving infrared light with the preset frequency fluctuation, the output level signal is a first level; when receiving constant infrared light or not receiving infrared light, the output level signal is a second level; the first level and the second level are opposite. The microprocessor receives the output level signal and determines the pulmonary function test result based on the output level signal. This invention can effectively distinguish between its own emitted infrared signal and infrared signals in ambient light, thus accurately measuring pulmonary function parameters even under strong ambient light, broadening the application scenarios of the pulmonary function instrument, and improving its ease of use and reliability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a pulmonary function instrument that resists ambient light interference, provided by this utility model.

[0018] Figure 2 This is a schematic diagram of the principle of a lung function instrument that resists ambient light interference provided by this utility model.

[0019] Figure 3 This is a schematic diagram illustrating the working principle of a turbine, an infrared emitting module, and an infrared receiving module in cooperation, as provided by this utility model.

[0020] Figure 4 This is a circuit diagram of the infrared emitting module provided by this utility model.

[0021] Figure 5 This is a circuit diagram of the infrared receiving module provided by this utility model.

[0022] Figure 6 This is the circuit schematic diagram of the microprocessor provided by this utility model.

[0023] Figure 7 This is a block diagram of the internal structure of the infrared receiving module provided by this utility model.

[0024] Figure 8 This is a schematic diagram illustrating the working principle of another turbine, infrared emitting module, and infrared receiving module provided by this utility model. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0026] Pulmonary function tests are an important means of diagnosing respiratory diseases. By measuring lung function, abnormalities in the respiratory system can be detected. This is of great guiding significance for the early detection of lung and respiratory tract lesions, such as chronic bronchitis, emphysema, bronchial asthma, and intermittent lung disease.

[0027] A pulmonary function analyzer is a device used in hospitals, clinics, and homes to examine various parameters of lung function. Current pulmonary function analyzers combine a turbine with infrared light acquisition. The air exhaled by the subject is converted into rotating airflow by the turbine, which drives the blades to rotate continuously. The infrared emitting and receiving modules within the pulmonary function analyzer are aligned with the blades. The emitting module generates infrared light, and as the blades rotate, the intensity of the light received by the receiving module varies depending on the blade angle, thus forming a signal that changes synchronously with the blade rotation. After processing by the signal processing circuit, these signals are converted into square wave signals synchronized with the blade rotation. Finally, the microprocessor further processes these signals to generate several major parameters for lung function measurement, including volume, flow rate, and time. Because the pulmonary function analyzer uses infrared light, excessively strong ambient light, such as from fluorescent lamps, dual ruby ​​lamps, infrared heaters, and direct sunlight, contains infrared radiation. This infrared light is the same as, and much stronger than, the constant infrared light emitted by the infrared emitting module. Therefore, in strong ambient light, infrared light can reach the infrared receiving module through the product's transparent casing, gaps, or even penetrating the casing. The receiving module, saturated with this large amount of infrared radiation, can no longer receive the weaker infrared light from the emitting module, which is blocked by the blades. Consequently, the receiving module cannot output a signal synchronized with the blade rotation, and therefore cannot generate a square wave signal, leading to inaccurate measurements or even malfunction. Thus, this device has strict environmental requirements and is particularly unsuitable for outdoor use, causing considerable inconvenience and limitations for users.

[0028] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a pulmonary function instrument that is resistant to ambient light interference, provided by this utility model.

[0029] Please refer to Figure 2 , Figure 2 This is a schematic diagram illustrating the principle of a pulmonary function instrument resistant to ambient light interference provided by this utility model.

[0030] Please refer to Figure 3 , Figure 3 This utility model provides a schematic diagram illustrating the working principle of a turbine, an infrared emitting module, and an infrared receiving module working together.

[0031] To address the technical problems existing in the prior art, this utility model provides a pulmonary function instrument resistant to ambient light interference, comprising: a microprocessor 1, which outputs a PWM control signal; an infrared emitting module 2, electrically connected to the microprocessor 1, which generates and emits infrared light with a preset frequency fluctuation based on the PWM control signal; a turbine assembly 3, which rotates under the action of the subject's exhaled air to intermittently block the infrared light with the preset frequency fluctuation; and an infrared receiving module 4, which is respectively disposed on both sides of the turbine assembly 3; the infrared receiving module 4 is electrically connected to the microprocessor 1 and outputs a first level signal when receiving infrared light with the preset frequency fluctuation; and outputs a second level signal when not receiving infrared light with the preset frequency fluctuation; the first level and the second level are opposite; the microprocessor 1 is also used to receive the output level signal and determine the pulmonary function test result based on the output level signal.

[0032] This embodiment provides a pulmonary function instrument resistant to ambient light interference, mainly comprising a microprocessor 1, an infrared emitting module 2, a turbine assembly 3, and an infrared receiving module 4. When a subject undergoes a pulmonary function test, exhaled air enters the air inlet of the pulmonary function instrument, driving the blades in the turbine assembly 3 to rotate. The microprocessor 1, as the core control unit, drives the infrared emitting module 2 to generate and emit infrared light (e.g., 940nm wavelength) fluctuating at a preset frequency (e.g., 38kHz or 56kHz) via a PWM control signal. The fluctuating infrared light emitted by the infrared emitting module 2 is blocked by the rotating blades, which is a carrier modulation process. The infrared light fluctuating at a certain frequency emitted by the infrared emitting module 2 is the carrier, and the infrared light blocked by the rotation of the blades is the data signal. When the blades rotate, they intermittently block the infrared light, resulting in the infrared receiving module 4 receiving a discontinuous fluctuating signal. Since the infrared radiation in ambient light is constant, while the infrared emitting module 2 emits fluctuating infrared signals, the infrared receiving module 4 is no longer saturated due to ambient light interference. It can effectively distinguish and ignore ambient light interference, allowing the pulmonary function instrument to operate normally. The infrared receiving module 4 generates an output level signal. When it receives infrared light fluctuating at a preset frequency, the output level signal is low (first level); when it does not receive infrared light fluctuating at the preset frequency (e.g., receiving constant infrared light or not receiving infrared light at all), the output level signal is high (second level). The microprocessor 1 detects the level signal output by the infrared receiving module 4, calculates the rotation frequency and speed of the blades, and then determines the subject's respiratory flow rate, velocity, and other pulmonary function parameters, ultimately outputting the test results. This embodiment effectively solves the technical problem that existing pulmonary function instruments cannot operate normally under strong ambient light. Even in strong outdoor light environments (e.g., outdoors on a sunny day with light intensity reaching 100,000 Lux), this pulmonary function instrument can still operate normally and accurately measure pulmonary function parameters, broadening its application scenarios and improving its ease of use, flexibility, and reliability. In addition, this design simplifies the circuit structure, reduces the failure rate, and improves the stability and lifespan of the equipment.

[0033] Please refer to Figure 4 , Figure 4 The circuit diagram of the infrared emitting module provided by this utility model.

[0034] In a preferred embodiment, the infrared emitting module 2 includes an infrared emitting tube, a MOSFET, a first resistor, and a second resistor; the first end of the first resistor is electrically connected to a power supply, the second end of the first resistor is electrically connected to the anode of the infrared emitting tube, the cathode of the infrared emitting tube is electrically connected to the drain of the MOSFET, the gate of the MOSFET is electrically connected to the first end of the second resistor, and the source of the MOSFET and the second end of the second resistor are both grounded.

[0035] In this embodiment, the infrared emitting module 2 is one of the key components of the pulmonary function instrument, which converts electrical signals into optical signals. It includes an infrared emitting diode (IR1), a MOSFET (Q-IR1), a first resistor (R-IR1), and a second resistor (R-IR2). The first terminal of the first resistor (R-IR1) is electrically connected to the power supply (VCC), and the second terminal is electrically connected to the anode of the infrared emitting diode (IR1), serving as a current limiter to ensure the infrared emitting diode operates within a safe current range and simultaneously limit circuit power consumption. The anode of the infrared emitting diode (IR1) is electrically connected to the power supply through the first resistor (R-IR1), and the cathode of the infrared emitting diode (IR1) is electrically connected to the drain of the MOSFET (Q-IR1). When the MOSFET is turned on, current flows through the infrared emitting diode, causing it to emit infrared light; when the MOSFET is turned off, the infrared emitting diode does not output infrared light. The gate of the MOSFET (Q-IR1) is electrically connected to the PWM control signal output terminal (NET_IR) of the microprocessor 1, the source of the MOSFET (Q-IR1) is grounded, and the drain of the MOSFET (Q-IR1) is electrically connected to the cathode of the infrared emitting diode. The MOSFET acts as a switching element, controlling the on / off state of the infrared emitting diode according to the PWM signal output by the microprocessor 1. The first terminal of the second resistor (R-IR2) is electrically connected to the PWM control signal output terminal (NET_IR) of the microprocessor 1, and the second terminal of the second resistor (R-IR2) is grounded, serving as a pull-down function to ensure that the gate of the MOSFET is in a low-level state when there is no PWM signal input, preventing false triggering. This embodiment features a simple circuit design with few components, making it easy to integrate into the overall circuit of the pulmonary function instrument, reducing manufacturing costs and complexity.

[0036] In a preferred embodiment, the turbine assembly 3 includes a turbine and turbine blades.

[0037] In this embodiment, the turbine assembly 3 is the core mechanical component of the pulmonary function analyzer, its main function being to convert the exhaled air of the subject into a measurable mechanical signal. The turbine is a cylindrical or conical main structure with an internal central shaft for supporting and fixing the turbine blades. The turbine housing is made of lightweight, high-strength materials, such as aluminum alloy or engineering plastics, to ensure its stability and durability during high-speed rotation. The central shaft of the turbine is connected to the microprocessor 1, which converts the rotational motion of the blades into an electrical signal and transmits it to the microprocessor 1. The blades are a key part of the turbine assembly 3; their shape and angle are specially designed to maximize the capture of airflow and its conversion into rotational motion. The blades are typically helical or arc-shaped, effectively guiding airflow and reducing energy loss. The number and distribution of the blades are also optimized to ensure smooth rotation and signal stability. The blades are manufactured using lightweight, high-strength materials, such as carbon fiber or high-strength plastics, to ensure their durability and reliability during high-speed rotation.

[0038] The turbine assembly 3 may also include a flow guide device for guiding airflow into the turbine. The flow guide device is located at the turbine inlet and is used to guide the airflow evenly onto the turbine blades to improve measurement accuracy. This embodiment is not particularly limited here.

[0039] Please refer to Figure 5 , Figure 5 The circuit diagram of the infrared receiving module provided by this utility model.

[0040] In a preferred embodiment, the infrared receiving module 4 includes an infrared receiving head, a capacitor, a third resistor, and a fourth resistor; the first end of the third resistor and the second end of the fourth resistor are both electrically connected to a power supply, the second end of the third resistor is electrically connected to the first end of the infrared receiving head and the first end of the capacitor, the second end of the fourth resistor is electrically connected to the second end of the infrared receiving head, and the third end of the infrared receiving head and the second end of the capacitor are both grounded.

[0041] In this embodiment, the infrared receiving module 4 converts optical signals into electrical signals, and includes an infrared receiver head (IRM), a capacitor (C-IRM1), a third resistor (R-IRM1), and a fourth resistor (R-IRM2). The first terminal of the infrared receiver head is electrically connected to the power supply (VCC), the second terminal (NET_IRM) outputs the processed electrical signal, and the third terminal is grounded (GND). The first terminal of the third resistor (R-IRM1) is electrically connected to the power supply (VCC), and the second terminal of the third resistor (R-IRM1) is electrically connected to both the first terminal of the infrared receiver head and the first terminal of the capacitor (C-IRM1). The function of the third resistor is to provide a stable power supply to the infrared receiver head and limit the current to prevent overload. The first terminal of the fourth resistor (R-IRM2) is electrically connected to the second terminal of the infrared receiver head, and the second terminal of the fourth resistor (R-IRM2) is grounded. The function of the fourth resistor is to provide pull-up or pull-down resistance for the output signal of the infrared receiver head, ensuring signal stability and reliability. The first terminal of capacitor (C-IRM1) is electrically connected to the second terminal of the third resistor (R-IRM1) and the first terminal of the infrared receiver head, and the second terminal of capacitor (C-IRM1) is grounded. The function of the capacitor is to filter out high-frequency noise in the power supply, improve the anti-interference capability of the infrared receiver head, and ensure signal stability. When the infrared receiving module 4 receives infrared light with a preset frequency fluctuation, the output signal is low (first level); when it receives constant infrared light or does not receive infrared light, the output signal is high (second level), forming a square wave signal that changes synchronously with the blade rotation. This eliminates the need for signal processing circuitry, simplifies the circuit structure, reduces the failure rate, and simplifies the manufacturing process.

[0042] Please refer to Figure 6 , Figure 6 The circuit schematic diagram of the microprocessor provided by this utility model.

[0043] The NET_IR interface of microprocessor 1 is electrically connected to the gate of the MOSFET, outputting a PWM control signal from infrared emitting module 2. The NET_IRM interface of microprocessor 1 is electrically connected to infrared receiving module 4 to acquire the output level signal.

[0044] Please refer to Figure 7 , Figure 7 The internal structure block diagram of the infrared receiving module provided by this utility model.

[0045] In a preferred embodiment, the infrared receiver head includes: a photodiode for converting received infrared light into a current signal; a gain amplifier electrically connected to the photodiode for amplifying the current signal output by the photodiode; a filter electrically connected to the gain amplifier for filtering the amplified signal output by the gain amplifier, filtering out signals corresponding to constant ambient infrared light, and outputting signals corresponding to infrared light fluctuating at a preset frequency; a demodulator electrically connected to the filter for demodulating the signals corresponding to infrared light fluctuating at a preset frequency and outputting a square wave signal; and a gain controller electrically connected to the gain amplifier for dynamically adjusting the gain of the gain amplifier through a closed-loop feedback mechanism.

[0046] In this embodiment, the infrared receiver head converts data-carrying infrared light into a reliable electrical signal—a signal that changes synchronously with the blade rotation—through a photoelectric conversion, amplification, filtering, and demodulation process. The key features are carrier modulation technology and circuit anti-interference design, enabling stable operation under strong ambient light. The infrared receiver head is a complex integrated component, internally incorporating a photodiode, gain amplifier, filter, demodulator, and gain controller. The photodiode is the front-end element of the infrared receiver head, responsible for converting the received infrared light into a current signal. When infrared light shines on the photodiode, the photoelectric effect generates a weak current, the intensity of which is proportional to the intensity of the received infrared light. The gain amplifier amplifies the weak current signal output from the photodiode for subsequent circuit processing. The gain amplifier is designed with a high-gain, low-noise operational amplifier to ensure no signal distortion during amplification. The filter is a crucial component, used to filter out signals corresponding to constant ambient infrared light from the amplified signal, retaining only signals corresponding to infrared light fluctuating at a preset frequency. The filter typically uses a bandpass filter, whose passband frequency matches the frequency emitted by the infrared emitting module 2 (e.g., 38kHz, 56kHz), effectively filtering out interference signals of other frequencies. The demodulator extracts the square wave signal corresponding to the infrared light fluctuating at a preset frequency from the filtered signal. The demodulator restores the original modulated signal, i.e., the pulse signal generated by the blade rotation, by removing the high-frequency carrier signal. The gain controller dynamically adjusts the gain of the gain amplifier through a closed-loop feedback mechanism to avoid signal overload (saturation) or weakness (insufficient signal-to-noise ratio), achieving dynamic adjustment of signal strength to adapt to changes in ambient light. When the ambient light intensity changes, the gain controller automatically adjusts the amplifier gain to ensure the stability of the output signal. If the input signal is too strong, the gain controller reduces the gain of the gain amplifier to avoid saturation; if the input signal is too weak, the gain controller increases the gain of the gain amplifier to ensure the signal can be demodulated. This dynamic adjustment mechanism enables the infrared receiver to maintain the stability and reliability of the output signal under different ambient light conditions. The gain controller can also be electrically connected to the filter and demodulator.

[0047] In addition, the demodulator can also be electrically connected to a transistor and a resistor to define the output signal level, outputting a high level or a low level, thus avoiding floating levels. This utility model does not impose any special limitations on this.

[0048] In a preferred embodiment, the infrared light emitted by the infrared emitting module 2 has a frequency range of 10~100kHz and a wavelength range of 750~2500nm.

[0049] In this embodiment, the infrared light emitted by the infrared emitting module 2 has a frequency range of 10kHz to 100kHz. Infrared light in ambient light is typically constant or low-frequency, while higher-frequency infrared signals can effectively distinguish the emitted signal from infrared signals in ambient light, thereby improving anti-interference capabilities. Higher-frequency signals are also easier for the subsequent infrared receiving module 4 to process, especially during demodulation and filtering, enabling more accurate extraction of the modulated signal. Within the 10kHz to 100kHz frequency range, infrared signals are safe for the human body and will not cause any harm to the user, meeting the safety standards for medical devices.

[0050] The infrared emitting module 2 emits infrared light with a wavelength range of 750nm to 2500nm. Within this wavelength range, infrared light can effectively penetrate the air and, after being modulated by the turbine blades, can be accurately received by the infrared receiving module 4. Infrared light in the 750nm to 2500nm wavelength range experiences less interference from common ambient light (such as sunlight and fluorescent lamps), effectively improving measurement accuracy. The infrared emitting tube and receiving head exhibit high efficiency and stability within this wavelength range, ensuring reliable signal transmission and reception.

[0051] Please refer to Figure 8 , Figure 8 This is a schematic diagram illustrating the working principle of another turbine, infrared emitting module, and infrared receiving module provided by this utility model.

[0052] In a preferred embodiment, the number of infrared emitting modules 2 and infrared receiving modules 4 is one pair or more pairs.

[0053] In this embodiment, the number of infrared emitting modules 2 and infrared receiving modules 4 in the ambient light interference resistant pulmonary function instrument can be one pair or more pairs. This design provides flexibility to meet the needs of different application scenarios and accuracy requirements.

[0054] In its most basic configuration, the pulmonary function analyzer includes a pair of infrared emitting modules 2 and infrared receiving modules 4. These modules are mounted on either side of a turbine assembly 3, ensuring that the infrared light is effectively modulated as airflow passes through the turbine. When the subject exhales air, it drives the turbine blades to rotate, intermittently blocking the infrared light. The infrared receiving module receives the modulated signal, converts it into an electrical signal, and transmits it to the microprocessor 1 for processing. This single-module configuration is suitable for general measurement needs and provides basic pulmonary function parameter measurements.

[0055] To improve measurement accuracy and reliability, the pulmonary function analyzer can be configured with multiple pairs of infrared emitting modules 2 and receiving modules. These modules can be evenly distributed along the circumference of the turbine or arranged according to specific design requirements. In a multi-pair module configuration, each pair of modules operates independently, but their output signals are processed uniformly by the microprocessor 1. By simultaneously receiving modulated infrared signals from multiple pairs of modules, the microprocessor 1 can perform data fusion and error correction, thereby improving measurement accuracy and stability, and further enhancing the system's robustness. For example, if one pair of modules is affected by localized ambient light interference, the data from other modules can serve as redundant information, ensuring the accuracy of the measurement results.

[0056] In a preferred embodiment, the infrared emitting module 2 and the infrared receiving module 4 are arranged around the turbine assembly at a preset angle, and the same pair of infrared emitting modules 2 and infrared receiving modules 4 are symmetrically arranged with respect to the turbine assembly.

[0057] In this embodiment, the infrared emitting module 2 and the receiving module are evenly distributed along the circumference of the turbine assembly, forming a circular or arc-shaped arrangement. This arrangement ensures that infrared light is emitted and received from different directions, thereby improving the comprehensiveness and accuracy of the measurement. The angle between the modules can be preset according to the turbine size and measurement requirements. For example, if the turbine diameter is large, the angle between the modules can be appropriately reduced to ensure sufficient coverage; if the turbine diameter is small, the angle between the modules can be appropriately increased. Each pair of infrared emitting modules 2 and receiving modules is on the same straight line and symmetrically arranged relative to the turbine assembly, ensuring that the emitted infrared light can be directly received by the corresponding receiving module. This alignment method can minimize signal loss and interference, and improve measurement accuracy.

[0058] In practical applications, assume the pulmonary function analyzer is equipped with two pairs of infrared emitting modules 2 and infrared receiving modules 4, which are evenly arranged around the turbine at a preset angle (e.g., 60 degrees). Each pair of modules is on the same straight line, ensuring that the emitted infrared light can be directly received by the corresponding receiving module. When the subject undergoes a pulmonary function test, both pairs of modules work simultaneously, receiving the modulated infrared signal and transmitting it to the microprocessor 1. The microprocessor 1 performs comprehensive analysis of the signals from different directions, calculating parameters such as respiratory flow rate and velocity.

[0059] In a preferred embodiment, the microprocessor 1 is also used to monitor the transmission frequency of the infrared emitting module 2 and the receiving frequency of the infrared receiving module 4 in real time, and automatically adjust the PWM control signal when a frequency deviation is detected.

[0060] In this embodiment, the microprocessor 1 monitors the transmission frequency of the infrared transmitting module 2 and the receiving frequency of the infrared receiving module 4 in real time using an internal timer or an external frequency meter, and compares the sampling results with preset frequency values. The transmission frequency is determined by the PWM signal generated by the microprocessor 1, while the receiving frequency is obtained by analyzing the square wave signal output by the infrared receiving module 4. When the sampling result deviates from the preset frequency value, a frequency adjustment mechanism is triggered. The frequency deviation may be caused by environmental factors (such as temperature changes, power supply voltage fluctuations) or equipment aging. The microprocessor 1 calculates the frequency deviation to determine whether the frequency of the PWM control signal needs to be adjusted to correct the transmission and receiving frequencies until they return to the preset values. The adjustment process is closed-loop; the microprocessor 1 continuously monitors frequency changes to ensure the stability of the adjusted frequency. The adjustment process is achieved by changing the duty cycle or period of the PWM signal. Through this automatic adjustment mechanism, the pulmonary function instrument can maintain stable measurement performance under environmental changes, ensuring the accuracy of the measurement results.

[0061] In a preferred embodiment, the pulmonary function instrument also includes a housing with a sealed structure to prevent ambient light from directly entering the optical path of the infrared emitting module 2 and the infrared receiving module 4.

[0062] In this embodiment, the ambient light-resistant pulmonary function instrument includes a sealed housing. The primary function of this housing is to prevent ambient light from directly entering the optical paths of the infrared emitting module 2 and the infrared receiving module 4, ensuring the device functions normally even under strong ambient light. The housing is made of opaque materials, such as engineering plastics or aluminum alloys. These materials not only effectively block the penetration of ambient light but also provide sufficient mechanical strength to protect the internal components from external physical damage. The surface of the housing undergoes special treatment, such as painting or coating, to further enhance its resistance to ambient light interference.

[0063] The internal casing features a multi-layered sealing structure, including gaskets, sealing rings, and sealant. These sealing elements are installed around the infrared emitting module 2 and the receiving module, ensuring complete isolation of the optical path from the external environment. The sealing structure is designed with the device's heat dissipation requirements in mind, employing a reasonable ventilation design and heat dissipation channels to ensure that the device's performance is not affected by heat buildup during prolonged operation.

[0064] In the optical path sections of the infrared emitting module 2 and the receiving module, a dedicated light-shielding plate and a light-guiding channel are installed inside the housing. The light-shielding plate blocks ambient light entering from the side, while the light-guiding channel ensures that infrared light can accurately reach the receiving module from the emitting module. The light-guiding channel is made of a high-reflectivity material, such as mirror aluminum or white polytetrafluoroethylene, to reduce light loss during transmission and improve measurement sensitivity.

[0065] In practical applications, it is assumed that the pulmonary function analyzer is subjected to strong sunlight interference when used outdoors. Due to the sealed structure of the casing, ambient light cannot directly enter the optical path of the infrared emitting module 2 and the receiving module. Even in a sunny outdoor environment with light intensity reaching 100,000 Lux, the device can still operate normally and provide accurate measurement results. The sealed structure not only protects the internal components from interference from ambient light but also ensures the stability and reliability of the device during long-term use. Through this design, the pulmonary function analyzer can provide reliable data support for medical diagnosis in various complex environments.

[0066] In addition, the pulmonary function instrument may also include an alarm device, a data storage module, a user interface module, a power supply module, and a wireless communication module, which are not specifically limited herein.

[0067] When the microprocessor 1 detects abnormal ambient light interference or abnormal measurement data, it issues an alarm signal through the alarm device to remind the user to check or remeasure.

[0068] The microprocessor 1 stores the measured lung function test results in the data storage module, and the user can read the test results through an external device.

[0069] The user interface module is used to display measurement results, operation prompts, and alarm information. The user interface module includes a display screen and operation buttons.

[0070] The power module is used to provide a stable power supply for the microprocessor 1, the infrared emitting module, the infrared receiving module and other electronic components. The power module includes a battery and a charging interface.

[0071] The microprocessor 1 transmits the measurement results to external devices via a wireless communication module that supports Bluetooth, Wi-Fi (Wireless Fidelity), or NFC (Near Field Communication) communication methods.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A pulmonary function instrument resistant to ambient light interference, characterized in that, include: The microprocessor is used to output PWM control signals; An infrared emitting module, electrically connected to the microprocessor, is used to generate and emit infrared light with a preset frequency fluctuation based on the PWM control signal; A turbine assembly is used to rotate under the action of the subject's exhaled gas to intermittently block the infrared light that fluctuates at the preset frequency; An infrared receiving module is provided, wherein the infrared emitting module and the infrared receiving module are respectively disposed on both sides of the turbine assembly; the infrared receiving module is electrically connected to the microprocessor and is used to generate an output level signal, and when receiving infrared light with a preset frequency fluctuation, the output level signal is a first level; In the absence of infrared light fluctuating at the preset frequency, the output level is the second level; the first level is the opposite of the second level. The microprocessor is also configured to receive the output level signal and determine the lung function test result based on the output level signal.

2. The pulmonary function instrument resistant to ambient light interference according to claim 1, characterized in that, The infrared emitting module includes an infrared emitting tube, a MOSFET, a first resistor, and a second resistor. The first end of the first resistor is electrically connected to the power supply, the second end of the first resistor is electrically connected to the anode of the infrared emitting diode, the cathode of the infrared emitting diode is electrically connected to the drain of the MOS transistor, the gate of the MOS transistor is electrically connected to the first end of the second resistor, and the source of the MOS transistor and the second end of the second resistor are both grounded.

3. The pulmonary function instrument resistant to ambient light interference according to claim 1, characterized in that, The turbine assembly includes a turbine and turbine blades.

4. The pulmonary function instrument resistant to ambient light interference according to claim 1, characterized in that, The infrared receiving module includes an infrared receiver head, a capacitor, a third resistor, and a fourth resistor; The first end of the third resistor and the second end of the fourth resistor are both electrically connected to the power supply. The second end of the third resistor is electrically connected to the first end of the infrared receiver and the first end of the capacitor, respectively. The second end of the fourth resistor is electrically connected to the second end of the infrared receiver. The third end of the infrared receiver and the second end of the capacitor are both grounded.

5. The pulmonary function instrument resistant to ambient light interference according to claim 4, characterized in that, The infrared receiver head includes: A photodiode is used to convert received infrared light into an electrical signal; A gain amplifier, electrically connected to the photodiode, is used to amplify the current signal output by the photodiode; The filter, electrically connected to the gain amplifier, is used to filter the amplified signal output by the gain amplifier, filter out the signal corresponding to the constant infrared light in the environment, and output the signal corresponding to the infrared light fluctuating at the preset frequency. The demodulator, electrically connected to the filter, is used to demodulate the signal corresponding to the infrared light fluctuating at the preset frequency and output a square wave signal. A gain controller, electrically connected to the gain amplifier, is used to dynamically adjust the gain of the gain amplifier through a closed-loop feedback mechanism.

6. The pulmonary function instrument resistant to ambient light interference according to claim 1, characterized in that, The infrared emitting module emits infrared light with a frequency range of 10~100kHz and a wavelength range of 750~2500nm.

7. The pulmonary function instrument resistant to ambient light interference according to claim 1, characterized in that, The number of infrared emitting modules and infrared receiving modules is one pair or more.

8. The pulmonary function instrument resistant to ambient light interference according to claim 1, characterized in that, The infrared emitting module and the infrared receiving module are arranged at preset angular intervals around the turbine assembly, and the same pair of infrared emitting modules and infrared receiving modules are symmetrically arranged relative to the turbine assembly.

9. The pulmonary function instrument resistant to ambient light interference according to claim 1, characterized in that, The microprocessor is also used to monitor the transmission frequency of the infrared emitting module and the receiving frequency of the infrared receiving module in real time, and automatically adjust the PWM control signal when a frequency deviation is detected.

10. The pulmonary function instrument resistant to ambient light interference according to any one of claims 1 to 9, characterized in that, The pulmonary function instrument also includes a housing with a sealed structure to prevent ambient light from directly entering the optical path of the infrared emitting module and the infrared receiving module.

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