Water film sensor and its liquid thickness detection method, liquid thickness detection component and its liquid detection method

Abstract

A water film sensor and its liquid thickness detection method, a liquid thickness detection component and its liquid detection method are disclosed. The water film sensor includes: an optical interference cavity, a first end of which has a water film capable of deformation under force, the side of the water film facing the optical interference cavity being a light-reflecting surface, and a light-reflecting film on the inner surface of the second end of the optical interference cavity; and an optical transceiver end, optically coupled to the optical interference cavity, for receiving laser signals and emitting interference light, the interference light being formed by the laser signal reciprocating between the light-reflecting surface and the light-reflecting film; wherein the deformation direction of the water film under force is towards or away from the optical interference cavity; and the laser signal enters the optical interference cavity from the second end. This invention can detect the thickness of dynamic or static water accumulation in a static state and has good measurement accuracy.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and in particular to a water film sensor and a liquid thickness detection method thereof, a liquid thickness detection component and a liquid detection method thereof. Background Technology

[0002] Currently, most airport runways are made of cement concrete. In rainy weather or when there is standing water, aircraft are prone to hydroplaning during takeoff, which can even lead to traffic accidents. This can range from blocking the runway to causing loss of life and property for passengers.

[0003] In existing pavement water film monitoring technologies, passive radar detection technology, mobile infrared spectroscopy, or capacitive sensing technology can be used. However, these technologies have problems such as poor measurement accuracy, inability to measure in a static state, or inability to detect the thickness of static water accumulation. Summary of the Invention

[0004] The technical problem solved by this invention is to provide a water film sensor and a liquid thickness detection method thereof, a liquid thickness detection component and a liquid detection method thereof, which can detect the thickness of dynamic or static water accumulation in a static state and has good measurement accuracy.

[0005] To address the aforementioned technical problems, this invention provides a water film sensor, comprising: an optical interference cavity, a first end of which has a water film capable of deformation under stress, the side of the water film facing the optical interference cavity being a light-reflecting surface, and a light-reflecting film on the inner surface of the second end of the optical interference cavity; and an optical transceiver, optically coupled to the optical interference cavity, for receiving laser signals and emitting interference light, wherein the interference light is formed by the laser signal reciprocating between the light-reflecting surface and the light-reflecting film; wherein the deformation direction of the water film under stress is towards or away from the optical interference cavity; and the laser signal enters the optical interference cavity from the second end of the optical interference cavity.

[0006] Optionally, a reflective material is coated on the side of the water film facing the optical interference cavity to form the light-reflecting surface.

[0007] To address the aforementioned technical problems, this invention provides a liquid thickness detection method based on the water film sensor described above, comprising: receiving interference light emitted by the water film sensor; detecting the wavelength value of the interference light based on a preset longitudinal modulus; calculating the effective cavity length of the optical interference cavity of the water film sensor based on the product of the wavelength value and the preset longitudinal modulus; determining the pressure exerted on the water film based on the effective cavity length; and determining the thickness of the liquid on the side of the water film away from the optical interference cavity based on the pressure exerted on the water film.

[0008] Optionally, the effective cavity length of the optical interference cavity of the water film sensor can be calculated using the following formula, based on the product of the wavelength value and the preset longitudinal modulus:

[0009]

[0010] Among them, L k (t) represents the effective cavity length of the optical interference cavity of the water film sensor, k represents the preset longitudinal modulus, and λ k (t) represents the wavelength value of the interference light.

[0011] Optionally, the pressure on the water film can be determined using the following formula based on the effective cavity length:

[0012] P k (t)=KL k (t)

[0013] Among them, P k (t) represents the pressure exerted on the water film, K represents the calibration coefficient, and L k (t) represents the effective cavity length of the optical interference cavity of the water film sensor.

[0014] Optionally, the thickness of the liquid on the side of the water film away from the optical interference cavity can be determined using the following formula, based on the pressure exerted on the water film:

[0015]

[0016] Among them, h k (t) represents the thickness of the liquid on the side of the water film away from the optical interference cavity, K represents the calibration coefficient, and L k (t) represents the effective cavity length of the optical interference cavity of the water film sensor, ρ represents the density of the liquid, and g represents the gravitational acceleration.

[0017] Optionally, the thickness of the liquid on the side of the water film away from the optical interference cavity can be determined using the following formula, based on the pressure exerted on the water film:

[0018]

[0019] Among them, h k (t) represents the thickness of the liquid on the side of the water film away from the optical interference cavity, K represents the calibration coefficient, and L k (t) represents the effective cavity length of the optical interference cavity of the water film sensor, ρ represents the density of the liquid, g represents the gravitational acceleration, and ΔP cUsed to represent corrected atmospheric pressure. To solve the above technical problems, embodiments of the present invention provide a liquid thickness detection component, including: a water film sensor; a liquid detection sensor comprising an optical fiber lens and an optical reflector, wherein the reflective surface of the optical reflector faces the optical fiber lens, and the distance between the reflective surface of the optical reflector and the optical fiber lens is fixed; wherein, the optical fiber lens is used to receive laser signals and emit them to the optical reflector, and then receive the laser reflection signals reflected from the optical reflector.

[0020] Optionally, the light transmittance of the material of the light reflector is greater than a preset light transmittance.

[0021] Optionally, the liquid thickness detection component further includes: an optical power detection module, which is integrated or separately installed on the liquid detection sensor; the optical power detection module is used to determine the first power of the laser signal emitted by the fiber optic lens to the optical reflector and the second power of the laser reflection signal.

[0022] Optionally, the optical interference cavity of the water film sensor is placed vertically, and the side of the water film in contact with the liquid is perpendicular to the ground and faces upward.

[0023] Optionally, the liquid thickness detection component further includes a pressure sensor for detecting the current atmospheric pressure.

[0024] To address the aforementioned technical problems, this invention provides a liquid detection method based on the liquid thickness detection component described above, comprising: receiving a laser signal using the fiber optic lens and transmitting it to the optical reflector, then receiving a laser reflection signal reflected from the optical reflector; determining a first power of the laser signal emitted by the fiber optic lens to the optical reflector and a second power of the laser reflection signal using an optical power detection module; and determining that liquid is deposited on the surface of the liquid detection sensor if the quotient of the second power and the first power is less than 1.

[0025] Compared with the prior art, the technical solution of the embodiments of the present invention has the following beneficial effects:

[0026] In this embodiment of the invention, a water film sensor including an optical interference cavity is provided. The first end of the optical interference cavity has a water film that can deform under force, so that the water film can bend into the optical interference cavity by the weight of the liquid, and the cavity length of the optical interference cavity changes. Then, the real-time thickness of the liquid can be determined by using the principle of the optical interference cavity.

[0027] Furthermore, by coating the side of the water film facing the optical interference cavity with a reflective material to form the light-reflecting surface, the bending of the water film can be made more sensitive, and the influence of the liquid's own weight can be better reflected.

[0028] Furthermore, the interference light emitted by the water film sensor is received, and the wavelength value of the interference light is detected based on a preset longitudinal modulus. The effective cavity length of the optical interference cavity of the water film sensor is calculated, the pressure on the water film is determined, and the thickness of the liquid on the side of the water film away from the optical interference cavity is determined. Using the above scheme, by locking the longitudinal modulus and detecting the wavelength value of the interference light corresponding to that longitudinal modulus, the effective cavity length of the interference cavity can be determined, i.e., the cavity length after deformation under liquid pressure, thus allowing for real-time determination of the current liquid thickness.

[0029] Furthermore, a liquid thickness detection component is provided, which may also include a liquid detection sensor. The included fiber optic lens is capable of receiving a laser signal and emitting it to the light reflector, and then receiving the laser reflection signal reflected from the light reflector. Thus, the surface of the liquid detection sensor can be determined to be deposited with liquid by using the first power of the laser signal emitted by the fiber optic lens to the light reflector and the second power of the laser reflection signal. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a water film sensor according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the optical interference cavity in a water film sensor in an embodiment of the present invention, where the water film is in an undeformed state;

[0032] Figure 3 This is a schematic diagram of the optical interference cavity in a water film sensor under deformed state in an embodiment of the present invention;

[0033] Figure 4 This is a flowchart of a liquid thickness detection method based on a water film sensor according to an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of the spectrum output from an optical interference cavity in an embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of the structure of a liquid thickness detection component in an embodiment of the present invention;

[0036] Figure 7 This is a schematic diagram of the structure of a liquid detection sensor according to an embodiment of the present invention;

[0037] Figure 8 This is a flowchart of a liquid detection method using a liquid thickness detection component according to an embodiment of the present invention. Detailed Implementation

[0038] In existing pavement water film monitoring technologies, passive radar detection technology, mobile infrared spectroscopy, or capacitive sensing technology can be used. However, these technologies have problems such as poor measurement accuracy, inability to measure in a static state, or inability to detect the thickness of static water accumulation.

[0039] The inventors of this invention discovered through research that in an existing pavement water film monitoring technology, a passive radar detection technology can be used, which needs to be embedded in the runway surface. Its detection end cannot be obstructed, and the measurement accuracy is slightly worse.

[0040] Another existing technology for monitoring runway water film can be mobile infrared spectroscopy, which uses spectral absorption peaks to identify substances. However, if the water film is thick, the detection accuracy is poor. Furthermore, mobile infrared spectroscopy requires mounting the detector on a ground patrol vehicle and taking measurements while in motion. The movement of the patrol vehicle along the runway side may pose a safety hazard to aircraft takeoff and landing.

[0041] Another existing pavement water film monitoring technology can use capacitive sensing technology. However, capacitive sensing technology cannot detect objects that are stationary on the sensor. Therefore, it can only be used for dynamic detection during rain or when water is flowing, and cannot detect the thickness of stationary water.

[0042] In this embodiment of the invention, a water film sensor including an optical interference cavity is provided. The first end of the optical interference cavity has a water film that can deform under force, so that the water film can bend into the optical interference cavity by the weight of the liquid, and the cavity length of the optical interference cavity changes. Then, the real-time thickness of the liquid can be determined by using the principle of the optical interference cavity.

[0043] To make the above-mentioned objectives, features and beneficial effects of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0044] Reference Figure 1 , Figure 1 This is a schematic diagram of the structure of a water film sensor according to an embodiment of the present invention. The water film sensor may include an optical interference cavity 12 and an optical transceiver 13.

[0045] The first end of the optical interference cavity 12 may have a water film 11 that can deform under force, and the side of the water film 11 facing the optical interference cavity 12 is a light reflecting surface 111. The inner surface of the second end of the optical interference cavity 12 is provided with a light reflecting film 121.

[0046] The optical transceiver 13 is optically coupled to the optical interference cavity 12 and is used to receive laser signals and emit interference light. The interference light is formed by the laser signal being reflected back and forth between the light reflecting surface 111 and the light reflecting film 121.

[0047] The water film 11 deforms towards or away from the optical interference cavity 12 when subjected to force, and the laser signal enters the optical interference cavity 12 from the second end of the optical interference cavity 12.

[0048] Specifically, the laser signal can be input through the optical fiber 14, enter the optical interference cavity 12 from the second end of the optical interference cavity 12 via the light reflection film 121, and the interference light can be output through the optical fiber 14.

[0049] Furthermore, the material of the water film 11 can be a metallic material, thereby possessing both deformation characteristics and light reflection characteristics.

[0050] Furthermore, a reflective material can be coated on the side of the water film 11 facing the optical interference cavity 12 to form the light reflecting surface 111.

[0051] In this embodiment of the invention, a reflective material is coated on the side of the water film 11 facing the optical interference cavity. Compared with additionally attaching a light-reflecting film with reflective capabilities, the coating method can make the water film 11 more sensitive to bending and better reflect the influence of the liquid's own weight.

[0052] Furthermore, the material of the water film 11 can be a metal material, and the light reflectivity of the water film 11 can be greater than the preset reflectivity, so that it has the characteristic of light reflection without additional coating or bonding.

[0053] Combined with reference Figure 2 and Figure 3 , Figure 2 This is a schematic diagram of the optical interference cavity in a water film sensor in an embodiment of the present invention, where the water film is in an undeformed state; Figure 3 This is a schematic diagram of the optical interference cavity in a water film sensor under deformed state in an embodiment of the present invention.

[0054] It is understandable that when a beam of light enters the optical interference cavity 12, the incident light wave and the reflected light wave interfere with each other, and after repeated reflections between the light reflecting surface 111 and the light reflecting film 121 at both ends, the light wave will interfere to form a standing wave.

[0055] When the water film 11 is in an undeformed state, the cavity length of the optical interference cavity 12 is the distance L1 between the light reflecting surface 111 and the light reflecting film 121.

[0056] When the water film 11 is in a deformed state, the deformation of the water film 11 causes the cavity length of the optical interference cavity 12 to change. The cavity length of the optical interference cavity 12 is the distance L2 between the light reflecting surface 111 and the light reflecting film 121.

[0057] The water film 11 deforms towards or away from the optical interference cavity 12 when subjected to force.

[0058] It is understandable that, such as Figure 3 When the water film 11 shown is subjected to downward pressure, such as the pressure of the liquid's own weight, L2 < L1; when the water film 11 is subjected to upward pressure, such as atmospheric pressure, and the water film 11 bulges upward, L2 > L1.

[0059] In this embodiment of the invention, a water film sensor including an optical interference cavity 12 is provided. The first end of the optical interference cavity 12 has a water film 11 that can deform under force, so that the water film 11 can be bent into the optical interference cavity 12 by the weight of the liquid, and the cavity length of the optical interference cavity 12 changes. Then, the real-time thickness of the liquid can be determined by using the principle of the optical interference cavity 12.

[0060] Reference Figure 4 , Figure 4 This is a flowchart of a liquid thickness detection method based on a water film sensor according to an embodiment of the present invention. The liquid thickness detection method may include steps S41 to S44:

[0061] Step S41: Receive the interference light emitted by the water film sensor, and detect the wavelength value of the interference light based on a preset longitudinal modulus;

[0062] Step S42: Calculate the effective cavity length of the optical interference cavity of the water film sensor based on the product of the wavelength value and the preset longitudinal modulus;

[0063] Step S43: Determine the pressure on the water film based on the effective cavity length;

[0064] Step S44: Determine the thickness of the liquid on the side of the water film away from the optical interference cavity based on the pressure exerted on the water film.

[0065] In the specific implementation of step S41, the wavelength value of the interference light can be determined based on the longitudinal modulus.

[0066] Reference Figure 5 , Figure 5 This is a schematic diagram of the spectrum output from an optical interference cavity in an embodiment of the present invention.

[0067] Specifically, the spectrum of transmitted light or the cepstrum of reflected light from an optical interference cavity will form a comb-shaped spectrum with a certain peak-to-peak spacing, and the distance between the peaks is called the peak-to-peak spacing.

[0068] The spectrum output from the optical interference cavity can be a cepstrum of the transmission spectrum or the reflection spectrum. Specifically, the spectrum output after transmission from the other side of the light source input side of the optical interference cavity is the transmission spectrum. Figure 5 The comb-shaped spectrum with a certain peak-to-peak spacing shown can be directly analyzed from the transmission spectrum; the spectrum output after reflection from the light source input side of the optical interference cavity is the reflection spectrum, from which the cepstrum can be calculated. Figure 5 The comb-shaped spectrum with a certain peak-to-peak spacing is shown, and then the cepstrum is analyzed.

[0069] It should be noted that the laser emitting the laser signal can be a wavelength scanning laser, which can have a fixed scanning bandwidth, such as 20nm, 40nm, 80nm, etc. The bandwidth of the laser can also be called laser bandwidth, optical bandwidth, scanning bandwidth, or operating bandwidth, and the width of the bandwidth can be determined based on the full width at half maximum (FWHM).

[0070] Taking a laser with a bandwidth of 40nm as an example, its output wavelength continuously scans within the range of 1520nm to 1560nm, and a peak signal that conforms to the range of 1520nm to 1560nm is scanned in the comb-shaped spectrum.

[0071] It should be noted that each peak has its own longitudinal modulus, such as Figure 5 The peak of the k-th mode (i.e., the longitudinal mode number is k) is shown. At time t1, the spectral peak corresponding to the k-th mode is in the undeformed state of the water film, and its wavelength value is λ1(k1,t1); at time t2, the spectral peak corresponding to the k-th mode is in the deformed state of the water film, and its wavelength value is λ2(k2,t2).

[0072] In practice, by locking the longitudinal modulus, the wavelength of the interference light corresponding to that longitudinal modulus can be detected, and then the effective cavity length of the current optical interference cavity can be calculated.

[0073] Continue to refer to Figure 4 In the specific implementation of step S42, the effective cavity length of the optical interference cavity of the water film sensor can be calculated using the following formula based on the product of the wavelength value and the preset longitudinal modulus:

[0074]

[0075] Among them, L k(t) represents the effective cavity length of the optical interference cavity of the water film sensor, k represents the preset longitudinal modulus, and λ k (t) represents the wavelength value of the interference light.

[0076] It is understandable that when the water film is in a deformed state, the deformation of the water film causes a change in the cavity length of the optical interference cavity. The effective cavity length of the optical interference cavity can be the current distance between the light reflecting surface and the light reflecting film, such as... Figure 3 The spacing L2 is shown.

[0077] In the specific implementation of step S43, the pressure on the water film can be determined using the following formula based on the effective cavity length:

[0078] P k (t)=KL k (t)

[0079] Among them, P k (t) represents the pressure exerted on the water film, K represents the calibration coefficient, and L k (t) represents the effective cavity length of the optical interference cavity of the water film sensor.

[0080] The calibration coefficient K can be obtained from historical or empirical data, or it can be determined by creating a fitting formula.

[0081] Specifically, experiments can be conducted beforehand, such as applying a known pressure to a water film and detecting the deformation of the water film to determine the effective cavity length of the optical interference cavity of the water film sensor. Then, the applied pressure can be increased or decreased sequentially, and the deformation of the water film can be detected again to determine the effective cavity length of the optical interference cavity of the water film sensor. This allows for the determination of the mapping relationship between the applied pressure and the effective cavity length of the optical interference cavity. A fitting formula can then be created based on this mapping relationship, so that the pressure on the water film can be determined in subsequent steps based on the effective cavity length.

[0082] In one specific embodiment of step S44, the thickness of the liquid on the side of the water film away from the optical interference cavity can be determined using the following formula, based on the pressure exerted on the water film:

[0083]

[0084] Among them, h k (t) represents the thickness of the liquid on the side of the water film away from the optical interference cavity, K represents the calibration coefficient, and L k (t) represents the effective cavity length of the optical interference cavity of the water film sensor, ρ represents the density of the liquid, and g represents the gravitational acceleration.

[0085] Specifically, the general formula for liquid pressure is:

[0086] P = ρgh

[0087] According to P k (t)=KL k (t)=ρgh k From (t), we can obtain the above formula:

[0088]

[0089] In another specific embodiment of step S44, the thickness of the liquid on the side of the water film away from the optical interference cavity is determined using the following formula, based on the pressure exerted on the water film:

[0090]

[0091] Among them, h k (t) represents the thickness of the liquid on the side of the water film away from the optical interference cavity, K represents the calibration coefficient, and L k (t) represents the effective cavity length of the optical interference cavity of the water film sensor, ρ represents the density of the liquid, g represents the gravitational acceleration, and ΔP c Used to indicate corrected atmospheric pressure.

[0092] Wherein, ΔP c This can be used to represent the pressure difference between the atmospheric pressure at the current location and the atmospheric pressure at the manufacturing location of the water film sensor. It is understood that during the manufacturing of the water film sensor, the amount of gas encapsulated in the optical interference cavity is fixed. However, in working scenarios with different altitudes and latitudes, atmospheric pressure can vary significantly, and the water film in the optical interference cavity will be affected by this pressure difference, causing it to bulge or dent. In this embodiment of the invention, ΔP is introduced... c This parameter can correct the calculated liquid thickness, further improving the accuracy of determining the liquid thickness.

[0093] In this embodiment of the invention, by receiving the interference light emitted by the water film sensor, detecting the wavelength value of the interference light based on a preset longitudinal modulus, calculating the effective cavity length of the optical interference cavity of the water film sensor, determining the pressure exerted on the water film, and determining the thickness of the liquid on the side of the water film away from the optical interference cavity. Using this scheme, by locking the longitudinal modulus and detecting the wavelength value of the interference light corresponding to that longitudinal modulus, the effective cavity length of the interference cavity can be determined, i.e., the cavity length after being subjected to liquid pressure and deformation, thereby determining the current liquid thickness in real time.

[0094] In this embodiment of the invention, a liquid thickness detection device based on a water film sensor is also disclosed, which may include:

[0095] A wavelength detection module is used to receive the interference light emitted by the water film sensor and detect the wavelength value of the interference light based on a preset longitudinal modulus.

[0096] The effective cavity length determination module is used to calculate the effective cavity length of the optical interference cavity of the water film sensor based on the product of the wavelength value and the preset longitudinal modulus.

[0097] A pressure determination module is used to determine the pressure exerted on the water film based on the effective cavity length;

[0098] A liquid thickness determination module is used to determine the thickness of the liquid on the side of the water film away from the optical interference cavity based on the pressure exerted on the water film.

[0099] For details regarding the principle, implementation, and beneficial effects of this liquid thickness detection device based on a water film sensor, please refer to the preceding text. Figure 4 The description of the liquid thickness detection method based on the water film sensor shown is not repeated here.

[0100] Reference Figure 6 , Figure 6 This is a schematic diagram of the structure of a liquid thickness detection component in an embodiment of the present invention.

[0101] The liquid thickness detection component may include a water film sensor 61 and a liquid detection sensor 63, and may also include a pressure sensor 62.

[0102] The water film sensor 61 can be the one described above and... Figure 1 The water film sensor shown may include an optical interference cavity, the first end of which has a water film that can deform under stress.

[0103] Furthermore, the water film sensor 61 can be mounted on the surface of the base by one or more of the following methods: screw fastening, embedding, welding, gluing, and implantation.

[0104] Furthermore, the optical interference cavity of the water film sensor 61 can be placed vertically, with the side of the water film in contact with the liquid perpendicular to the ground and facing upwards, thereby effectively enabling the liquid to fall onto the water film and apply pressure to it. In this embodiment of the invention, the liquid thickness detection component can be pre-set in a fixed location, such as buried underground, and the dynamic or static water thickness can be detected in a static state through the exposed water film.

[0105] Furthermore, the liquid thickness detection component may also include a pressure sensor 62.

[0106] The pressure sensor 62 can be used to detect the current atmospheric pressure.

[0107] In this embodiment of the invention, atmospheric pressure can vary significantly in working scenarios at different altitudes and latitudes. By setting up a pressure sensor 62, the current atmospheric pressure can be detected in real time, thereby correcting the calculated liquid thickness and further improving the accuracy of determining the liquid thickness.

[0108] Furthermore, the liquid thickness detection component may also include a liquid detection sensor 63.

[0109] Reference Figure 7 , Figure 7 This is a schematic diagram of the structure of a liquid detection sensor according to an embodiment of the present invention.

[0110] The liquid detection sensor may include an optical fiber lens 71 and a light reflector 72.

[0111] The reflective surface of the light reflector 72 can face the fiber optic lens 71, and the distance between the reflective surface of the light reflector 72 and the fiber optic lens 71 is fixed.

[0112] exist Figure 7 In the liquid detection sensor shown, the distance between the reflective surface of the light reflector 72 and the fiber optic lens 71 can be maintained as d. That is, the material of the light reflector 72 can be a non-elastic material.

[0113] The fiber optic lens 71 is used to receive laser signals and transmit them to the light reflector 72, and then receive the laser reflection signals reflected from the light reflector 72.

[0114] The laser signal can be input through optical fiber 73.

[0115] Furthermore, the liquid thickness detection component may also include: an optical power detection module (not shown), which is integrated or separately installed on the liquid detection sensor; the optical power detection module is used to determine the first power of the laser signal emitted by the fiber optic lens 71 to the optical reflector 72 and the second power of the laser reflection signal.

[0116] In this embodiment of the invention, the liquid thickness detection component may further include a liquid detection sensor, which includes an optical fiber lens 71 capable of receiving a laser signal and emitting it to the light reflector 72, and then receiving the laser reflection signal reflected from the light reflector 72. Thus, the first power of the laser signal emitted by the optical fiber lens 71 to the light reflector and the second power of the laser reflection signal can be used to determine that liquid is deposited on the surface of the liquid detection sensor.

[0117] Continue to refer to Figure 6 When liquid is deposited on the surface of the liquid detection sensor 63, a water layer will form above the fiber optic lens. The water layer will reduce the light power of the reflected beam detected by the fiber optic lens, thereby determining whether there is liquid deposit on the surface of the liquid detection sensor 63, such as determining whether there is water accumulation on an airplane runway.

[0118] Furthermore, the light transmittance of the material of the light reflector is greater than the preset light transmittance.

[0119] In this embodiment of the invention, by setting the light transmittance of the material of the light reflector to be greater than the preset light transmittance, the water layer can be more sensitive to the reduction of the light power of the reflected light beam, thereby improving the accuracy of judgment.

[0120] Reference Figure 8 , Figure 8 This is a flowchart of a liquid detection method using a liquid thickness detection component according to an embodiment of the present invention.

[0121] The liquid detection method of the liquid thickness detection component may include steps S81 to S83:

[0122] Step S81: The fiber optic lens is used to receive the laser signal and transmit it to the optical reflector, and then the laser reflection signal reflected from the optical reflector is received;

[0123] Step S82: Use an optical power detection module to determine the first power of the laser signal emitted by the fiber optic lens to the optical reflector and the second power of the laser reflection signal;

[0124] Step S83: If the quotient of the second power and the first power is less than 1, then it is determined that liquid is deposited on the surface of the liquid detection sensor.

[0125] Furthermore, the quotient of the second power and the first power can be calculated using the following formula:

[0126]

[0127] Among them, I r P is used to represent the ratio of optical power, that is, the quotient of the second power and the first power. R P0 is used to represent the second power, and P0 is used to represent the first power.

[0128] It should be noted that the second power P R The optical power ratio I is greater than or equal to the first power P0. r Satisfying 0 < I r ≤1.

[0129] The liquid layer above the fiber optic lens reduces the optical power P of the reflected beam detected by the fiber optic lens. R , that is I r It will decrease, meaning the quotient of the second power and the first power will be less than 1. As the liquid layer thickness increases, I... r It will tend to 0.

[0130] In practice, a liquid detection sensor can be used first to detect whether liquid deposition exists. If liquid deposition is detected, a water film sensor can then be used to detect the liquid thickness.

[0131] In this embodiment of the invention, a liquid detection device based on a liquid thickness detection component is also disclosed, which may include:

[0132] The fiber optic lens control module is used to receive laser signals using the fiber optic lens and transmit them to the optical reflector, and then receive the laser reflection signals reflected from the optical reflector.

[0133] The optical power detection module control module is used to determine the first power of the laser signal emitted by the fiber optic lens to the optical reflector and the second power of the laser reflection signal using the optical power detection module;

[0134] A liquid deposition determination module is used to determine that liquid is deposited on the surface of the liquid detection sensor when the quotient of the second power and the first power is less than 1.

[0135] For details regarding the principle, implementation, and beneficial effects of this liquid detection device based on a liquid thickness detection component, please refer to the preceding text and... Figure 8 The description of the liquid detection method based on the liquid thickness detection component shown is not repeated here.

[0136] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A water film sensor, characterized in that, include: An optical interference cavity has a water film at its first end that can deform under force, and the side of the water film facing the optical interference cavity is a light-reflecting surface. A light-reflecting film is provided on the inner surface of the second end of the optical interference cavity. The optical transceiver is optically coupled to the optical interference cavity and is used to receive laser signals and emit interference light, which is formed by the laser signal being reflected back and forth between the optical reflective surface and the optical reflective film; the wavelength value of the interference light is detected based on a preset longitudinal modulus. The effective cavity length of the optical interference of the water film sensor is calculated based on the wavelength value and the preset longitudinal modulus: ， Among them, L k (t) represents the effective cavity length of the optical interference cavity of the water film sensor, k represents the preset longitudinal modulus, and λ k (t) represents the wavelength value of the interference light; The pressure exerted on the water film is determined based on the effective cavity length; P k (t)=KL k (t) Among them, P k (t) represents the pressure exerted on the water film, K represents the calibration coefficient, and L k (t) represents the effective cavity length of the optical interference cavity of the water film sensor; The thickness of the liquid on the side of the water film away from the optical interference cavity is determined based on the pressure exerted on the water film. ， Among them, h k (t) represents the thickness of the liquid on the side of the water film away from the optical interference cavity, K represents the calibration coefficient, and L k (t) represents the effective cavity length of the optical interference cavity of the water film sensor, ρ represents the density of the liquid, and g represents the gravitational acceleration. Wherein, the deformation direction of the water film when subjected to force is toward or away from the optical interference cavity; The laser signal enters the optical interference cavity from the second end of the optical interference cavity.

2. The water film sensor according to claim 1, characterized in that, A reflective material is coated on the side of the water film facing the optical interference cavity to form the light-reflecting surface.

3. The water film sensor according to claim 1 or 2, characterized in that, Atmospheric pressure was taken into account when calculating the liquid thickness. ， Among them, h k (t) represents the thickness of the liquid on the side of the water film away from the optical interference cavity, K represents the calibration coefficient, and L k (t) represents the effective cavity length of the optical interference cavity of the water film sensor, ρ represents the density of the liquid, g represents the gravitational acceleration, and ΔP c Used to indicate corrected atmospheric pressure.

4. A liquid thickness detection component, characterized in that, include: The water film sensor as described in any one of claims 1-3; A liquid detection sensor includes a fiber optic lens and a light reflector, wherein the reflective surface of the light reflector faces the fiber optic lens. Furthermore, the distance between the reflective surface of the light reflector and the fiber optic lens is fixed; The fiber optic lens is used to receive laser signals and transmit them to the optical reflector, and then receive the laser reflection signals reflected from the optical reflector.

5. The liquid thickness detection component according to claim 4, characterized in that, The light transmittance of the material of the light reflector is greater than the preset light transmittance.

6. The liquid thickness detection component according to claim 5, characterized in that, Also includes: An optical power detection module may be integrated or separately installed in the liquid detection sensor; The optical power detection module is used to determine the first power of the laser signal emitted by the fiber optic lens to the optical reflector and the second power of the laser reflection signal.

7. The liquid thickness detection component according to claim 6, characterized in that, The optical interference cavity of the water film sensor is placed vertically, and the side of the water film in contact with the liquid is perpendicular to the ground and faces upward.

8. The liquid thickness detection component according to claim 7, characterized in that, Also includes: A barometric pressure sensor is used to detect the current atmospheric pressure.

9. A liquid detection method based on the liquid thickness detection component according to any one of claims 4-8, characterized in that, include: The fiber optic lens is used to receive the laser signal and transmit it to the optical reflector, and then the laser reflection signal reflected from the optical reflector is received. The first power of the laser signal emitted by the fiber optic lens to the optical reflector is determined using an optical power detection module. and the second power of the laser reflection signal; If the quotient of the second power and the first power is less than 1, it is determined that liquid is deposited on the surface of the liquid detection sensor.

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