Marine biochemical optical sensor and detection method

Abstract

A marine biochemical optical sensor and detection method, comprising: a shell, a storage space is arranged in the shell, the storage space is formed with a first opening and a second opening on the shell; a cover, the cover is detachably connected with the shell through a connecting assembly; a signal transmission assembly, the signal transmission assembly is arranged on the second cover at the second opening; a detection assembly, the detection assembly is arranged on the first cover at the first opening, and is electrically connected with the signal transmission assembly through a control assembly in the storage space; the detection assembly comprises a detector 5 and three light sources 6, which are used for detecting chlorophyll information of water body, the simple optical structure of "three light sources and one detector" is the core, under the premise of not greatly increasing the hardware cost, volume and power consumption, the precision, stability and environmental adaptability of the marine chlorophyll single parameter detection are significantly improved. Cooperate with the nondestructive detachable connecting assembly, so that the sensor has deep sea high pressure reliability, on-site maintainability and long-term deployment consistency.

Description

Technical Field

[0001] This invention relates to the field of marine sensors, specifically to a marine biochemical optical sensor and detection method. Background Technology

[0002] In marine ecological environment monitoring, chlorophyll a concentration is a key parameter for evaluating primary productivity, algal biomass, and eutrophication status. Optical fluorescence sensors, due to their advantages such as real-time operation, in-situ detection, reagent-free operation, and long-term deployment, have become the mainstream technology for marine chlorophyll detection.

[0003] Currently, most optical sensors used for chlorophyll detection in water are single-parameter detection structures, typically operating with a single excitation light source and a single fluorescence detector. These sensors are relatively simple in structure, consume less power, and can meet basic monitoring needs under specific water conditions.

[0004] However, with the continuous improvement of marine observation precision and the increasing complexity of monitoring scenarios, existing single-parameter chlorophyll sensors have gradually revealed insufficient detection accuracy in practical applications. The main reason is that natural water bodies contain a wide variety of algae, and different algae have different optical response characteristics. A single excitation condition cannot fully cover the fluorescence excitation requirements of different algal populations, easily leading to measurement deviations. Furthermore, existing sensors often prioritize functional implementation in their optical structure design, lacking systematic optimization for detection signal-to-noise ratio, stray light suppression, and long-term consistency, further limiting the accuracy of quantitative chlorophyll detection.

[0005] Meanwhile, existing sensors also have many shortcomings in their engineering structure. On the one hand, the integration of optical elements, sealing windows and detection channels is relatively crude, making disassembly and maintenance difficult, and on-site replacement or cleaning often requires returning to the factory for processing; on the other hand, the connection between the housing and the cover mostly relies on traditional threaded structures, which are prone to seizing or sealing failure under long-term seawater corrosion and high-pressure alternating environments, seriously affecting the maintainability and life-cycle value of the sensor.

[0006] In summary, existing marine chlorophyll optical sensors have significant shortcomings in terms of detection accuracy, structural reliability, and ease of maintenance. Therefore, it is essential to provide a new marine biochemical optical sensor and detection method. Summary of the Invention

[0007] The purpose of this invention is to provide a marine biochemical optical sensor and detection method to improve the accuracy of chlorophyll detection in water and facilitate disassembly and assembly, thereby overcoming the shortcomings of existing technologies.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a marine biochemical optical sensor, comprising:

[0009] The housing has a storage space inside, and the storage space has a first opening at the lower end of the housing and a second opening at the upper end of the housing.

[0010] The cover, which is detachably connected to the housing via a connecting assembly, includes a first cover and a second cover, capable of covering and sealing the first opening and the second opening to close the storage space;

[0011] A signal transmission component is disposed on a second cover at the second opening;

[0012] A detection component is disposed on a first cover at a first opening, and the detection component is electrically connected to a signal transmission component through a control component disposed in a storage space.

[0013] The detection component includes a detector and three light sources for detecting chlorophyll information in the water.

[0014] Preferably, the first cover has two channels, with the three light sources disposed in one channel and the detector disposed in the other channel.

[0015] Preferably, the receiving wavelength of the detector is 695 nm;

[0016] The light source is configured with three excitation wavelengths of 435 nm, 470 nm and 532 nm, respectively. The light source with an excitation wavelength of 435 nm is used for auxiliary detection, the light source with an excitation wavelength of 532 nm is used for detection correction, and the light source with an excitation wavelength of 470 nm is used for primary detection.

[0017] Preferably, the connection component includes:

[0018] The first mounting groove is formed on the side wall of the cover and is an annular groove.

[0019] The second mounting slot is correspondingly formed on the inner side wall of the housing, and can communicate with the first mounting slot during installation;

[0020] The first connecting hole is formed on the side wall of the cover and communicates with the first mounting groove. The central axis of the first connecting hole is perpendicular to the central axis of the first mounting groove.

[0021] The second connecting hole is formed on the side wall of the housing and communicates with the second mounting groove. The central axis of the second connecting hole extends in the same direction as the central axis of the first connecting hole, and the second connecting hole can communicate with the first mounting groove.

[0022] The first connector can be simultaneously disposed in the first mounting groove and the second mounting groove, and its sidewall can simultaneously abut tightly against the inner wall of the first mounting groove and the inner wall of the second mounting groove. One end of the first connector can pass through the second connecting hole and enter the first mounting groove and the second mounting groove from one side of the first connecting hole, and extend out from the first mounting groove and the second mounting groove on the other side of the first connecting hole, and converge with the other end at the first connecting hole.

[0023] The second connector has one end that can pass through the second connection hole into the first connection hole, press both ends of the first connector into the first connection hole, and detachably connect them to the first connection hole. The other end can abut against the outer wall of the housing or be installed in the second connection hole.

[0024] In the aforementioned detachable connection between the second connector and the first connecting hole, if the first connecting hole is a through hole, then a seal is required between the two.

[0025] Preferably, the channel includes an installation area channel and a detection area channel. One end of the detection area channel is connected to the storage space, and the other end is connected to the installation area channel. The other end of the installation area channel has an opening formed on the outer end face of the first cover body, which is connected to the external space of the shell.

[0026] The detection component also includes a lens (sampling window) and a filter. The lens is disposed in the installation area channel and is sealed to the installation area channel, and can cover the opening formed on the outer end face of the installation area channel.

[0027] The detector, light source, and filter are all disposed in the detection area channel. The ends of the detector and light source that are away from the lens can extend into the detection area channel and be electrically connected to the control component. The filter is located between the detector and the lens, and also between the light source and the lens.

[0028] The filter in the channel where the detector is located is a 695nm narrowband filter, which allows chlorophyll a red fluorescence to pass through while suppressing blue-violet / blue / green excitation light and non-target fluorescence.

[0029] The light source is an LED, and the detector is a 695 nm photodiode.

[0030] Preferably, the storage space includes a connection area and a storage area, the portion of the housing located in the connection area is connected to the cover, and the storage area is used to store control components;

[0031] The inner diameter of the housing located in the connecting area is larger than the inner diameter of the housing located in the storage area, and the connecting area and the storage area are connected by a first abutting part;

[0032] The end of the cover that is away from the water can abut against the first abutting part;

[0033] Alternatively, the cover may be provided with a second abutment in the circumferential direction, one end of which is connected to the outer wall of the cover, and the other end extends away from the central axis of the cover, and the lower end face of the second abutment can abut tightly against the end face of the shell.

[0034] In this application, either the first abutment part or the second abutment part can be set, or both can be set.

[0035] Preferably, the connecting area is divided into a sealing area and a joining area, the joining area and the storage area are located on both sides of the sealing area, the inner diameter of the housing in the joining area, the sealing area and the storage area increases sequentially, the joining area and the sealing area are connected by a third abutment, and the sealing area and the storage area are connected by a first abutment.

[0036] A fourth abutment is provided on the side wall of the cover, and the fourth abutment abuts against the third abutment, and the two fit tightly together.

[0037] The second mounting groove is disposed in the mating area, and at least one sealing component is disposed on the sealing area. The component includes a third mounting groove and a sealing element. The third mounting groove is opened on the outer side wall of the cover, and the sealing element is disposed in the third mounting groove and can closely abut against the inner side wall of the housing.

[0038] Preferably, the control component includes:

[0039] The first circuit board is detachably connected to the first cover via a third connector, and the first circuit board is electrically connected to the detection component.

[0040] The second circuit board is located on both sides of the first cover. The second circuit board is connected to the first circuit board through a fourth connector, and the second circuit board is electrically connected to the first circuit board and the signal transmission component.

[0041] In this application, the signal transmission component is electrically connected to the second circuit board, using the configuration found in the prior art.

[0042] I. Parameter Settings

[0043] 1.1) Light source parameter settings: Excitation wavelengths of LEDs are 435nm, 470nm, and 532nm;

[0044] 1.2) Detector parameter settings: Configure a 695nm narrowband filter for the detector receiving wavelength of 695nm;

[0045] 1.3) Sampling parameters: For each measurement cycle, set the light source to be off and the dark field sampling, the number of repeated pulses N, the outlier removal threshold, and the calibration curves for each parameter;

[0046] II. Data Acquisition

[0047] 2.1) Dark field sampling: With all light sources turned off, measure the dark field / ambient light value of the detector as the background subtraction reference for this cycle;

[0048] 2.2) Auxiliary sampling: Only the 435nm LED is lit, and after stabilization, M ADC points are collected. This process is repeated N times to obtain the S435→695 data parameters, which are used as auxiliary data.

[0049] In this application, ADC is an abbreviation for Analog-to-Digital Converter. This is common in the prior art and will not be elaborated further here.

[0050] 2.3) Principal value sampling: The 435nm LED is turned off, and after the afterglow wait, only the 470nm LED is lit. After stabilization, M ADC points are collected, and N sets of S470→695 data parameters are collected as the chlorophyll a quantitative principal data.

[0051] 2.4) Correction sampling: Turn off the 470nm LED, wait for afterglow, and only turn on the 532nm LED. After stabilization, collect M ADC points and N sets of S532→695 data parameters as correction data.

[0052] III. Data Selection

[0053] 3.1) Preprocessing: Preprocess the data obtained from each parameter;

[0054] 3.2) Dark field subtraction is performed on the effective signals of each channel;

[0055] 3.3) Based on the data processed above, formulate calibration curves for each parameter and output the final effective values ​​of each parameter.

[0056] In this application, although the N sets of data obtained from the above different parameters are represented by the same letter, the N in different parameters may take the same value or different values ​​according to the actual use requirements, that is, it is not necessary for all N to represent the same data at the same time.

[0057] Preferably, in step 3.1), the preprocessing specifically includes:

[0058] 3.1.1) Take the average or median of the data from the M ADC points in each stable sampling window;

[0059] 3.1.2) Within one cycle (where at least one of the five parameters has corresponding monitoring data), the average value of N sets of pulse data is processed using the median, extreme value removal average, or standard deviation threshold-filtered average.

[0060] In this application, depending on the actual usage requirements, the processing methods for different parameters can be arbitrarily selected from the above three methods. The average value after standard deviation threshold filtering can be understood as the difference between the measured data and the preset standard value. If the difference exceeds the normal threshold, it is discarded. The average value of the data retained after the above filtering is taken.

[0061] 3.1.3) Remove outliers caused by bubbles, momentary occlusion by floating particles, and electrical noise based on the outlier removal threshold;

[0062] 3.1.4) The effective signals of each channel are subjected to dark field subtraction according to S=ADC_on-ADC_dark to obtain F435, F470 and F532.

[0063] In this application, ADC_on refers to the original signal value (including real signal + dark current noise) read by the detector when there is light source illumination (or signal acquisition is enabled), and ADC_dark refers to the dark field signal value (mainly dark current, bias and other background noise) read when there is no light source illumination (maintaining the same exposure time, temperature and other conditions).

[0064] Preferably, in step 3.3), the selection criteria for each parameter are as follows:

[0065] The basic output is based on the chlorophyll a value obtained from the calibration curve of F470.

[0066] When the F470 signal is in the linear range (preset) and R435 / 470 and R532 / 470 (Ratio) are in the normal calibration range (preset), the three-wavelength weighted average value is directly output.

[0067] When F435 / F470 is significantly higher or lower, F435 is used to correct F470, and the corrected value is output.

[0068] In step 3.1.2), the auxiliary data is processed by removing extreme values ​​and averaging S435→695, the chlorophyll a quantitative main data is processed by averaging the average value after standard deviation threshold screening, and the corrected data S532→695 is processed by taking the median.

[0069] Compared with the prior art, the beneficial effects of the present invention are:

[0070] 1. By integrating three light sources with different excitation characteristics and a dedicated detector within a single detection channel, this invention can acquire fluorescence response information of chlorophyll in water under various excitation conditions without increasing hardware complexity. Compared to traditional single-source excitation methods, this multi-source excitation structure effectively overcomes the measurement bias caused by inconsistent responses of different algal populations under a single excitation condition, making chlorophyll quantification results more accurate and stable, and is particularly suitable for marine waters with complex algal compositions or significant dynamic changes.

[0071] 2. The detection channel is equipped with a narrow-band filter that matches the characteristic fluorescence of chlorophyll, which can simultaneously suppress direct interference from various excitation lights, water scattering light, and crosstalk from non-target fluorescent substances (such as yellow substances and other pigments). This design significantly improves the signal-to-noise ratio of fluorescence detection, enabling the sensor to maintain high detection sensitivity and repeatability even in water with low chlorophyll concentration or high turbidity.

[0072] 3. The three light sources are lit independently and sequentially in chronological order, without simultaneous excitation. Combined with dark-field sampling (all light sources are turned off) before the start of each measurement cycle, ambient light, circuit background noise, and the sensor's own dark current can be effectively deducted. This timing design ensures no spectral overlap between the signals of each channel, further guaranteeing the purity and reliability of the detection data.

[0073] 4. The connecting component proposed in this invention allows for locking and unlocking by simply tightening or loosening one second connector. The assembly and disassembly process is simple, requires no special tools, does not damage the seals, and the time required for a single assembly or disassembly can be kept short. This design makes it possible to change the detection channel, clean the optical window, replace the seals, or perform laboratory calibration on-site, greatly extending the sensor's lifespan.

[0074] 5. The shell and cover employ a multi-stage abutment structure with multiple O-ring seals to form a pressure-reinforced seal. The connection components do not rely on threads to transmit axial force, avoiding seal failure caused by thread plastic deformation under high pressure. The sensor has a maximum operating depth of 6000 meters and is suitable for various deep-sea operation platforms such as profiling, mooring, buoys / submarine moors, and ROVs / AUVs. Meanwhile, the low-power circuit design and stable optical structure ensure data consistency for long-term unattended continuous observation.

[0075] 6. By comprehensively analyzing fluorescence data acquired under three excitation conditions (such as ratio judgment, anomaly identification, and weighted fusion), the sensor can autonomously identify whether there are abnormal interferences in the water body (such as bubbles, particulate matter obstruction, and light path contamination), and select the optimal output strategy under different signal quality conditions. Compared with traditional schemes that rely solely on a single signal path, the data processing method of this invention significantly improves the robustness and reliability of chlorophyll detection results. Attached Figure Description

[0076] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0077] Figure 2 This is the overall explosion intention in this invention;

[0078] Figure 3 This is a cross-sectional view of the overall structure in this invention;

[0079] Figure 4 In this invention Figure 2 The enlarged view shown at point A in the middle;

[0080] Figure 5 This is an exploded view of part of the structure in this invention;

[0081] Figure 6 This is a partial structural diagram of the present invention;

[0082] Figure 7 In this invention Figure 6 The enlarged view shown at point B in the middle;

[0083] In the diagram: 1. Housing; 2. Storage space; 3. Second cover; 4. First cover; 5. Detector; 6. Light source; 7. First mounting slot; 8. Second mounting slot; 9. First connecting hole; 10. Second connecting hole; 11. First connector; 12. Second connector; 13. Mounting area channel; 14. Detection area channel; 15. Lens; 16. Filter; 17. Storage area; 18. First abutment; 19. Second abutment; 20. Sealing area; 21. Joining area; 22. Fourth abutment; 23. Third mounting slot; 24. Seal; 25. First circuit board; 26. Third connector; 27. Second circuit board; 28. Fourth connector; 29. ​​Third abutment; 30. Signal transmission component; 31. Auxiliary part. Detailed Implementation

[0084] The following will refer to the appendices in the embodiments of the present invention. Figures 1-7 The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0085] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0086] Please see Figures 1-7 Embodiments of the present invention:

[0087] Example:

[0088] like Figure 1 As shown: a housing 1, the housing 1 having a storage space 2 inside, the storage space 2 having a first opening at the lower end of the housing 1 and a second opening at the upper end of the housing 1 at both ends;

[0089] The cover is detachably connected to the housing 1 via a connecting assembly. It includes a first cover 4 and a second cover 3, which can cover and seal the first opening and the second opening to close the storage space 2.

[0090] A signal transmission component 30 is disposed on the second cover 3 at the second opening;

[0091] The detection component is disposed on the first cover 4 at the first opening, and the detection component is electrically connected to the signal transmission component 30 through the control component disposed in the storage space 2.

[0092] The detection component includes a detector 5 and three light sources 6 for detecting chlorophyll information in the water.

[0093] like Figure 3 and Figure 6 As shown: The first cover 4 is provided with two channels, the three light sources 6 are provided in one channel, and the detector 5 is provided in the other channel.

[0094] The receiving wavelength of the detector 5 is 695 nm;

[0095] The light source 6 is provided in three parts, with excitation wavelengths of 435 nm, 470 nm and 532 nm respectively. The light source with an excitation wavelength of 435 nm is used for auxiliary detection, the light source with an excitation wavelength of 532 nm is used for detection correction, and the light source with an excitation wavelength of 470 nm is used for main detection.

[0096] In this embodiment, the light source 6 is a laser light source 6, using LEDs, and is located in the same channel. This application's HBOS-MPS (Hydro-Biochemical Optical Series–Multi-Parameter Sensor) is a biochemical optical sensor designed for long-term autonomous ocean observation. The sensor employs a stable LED excitation light source 6 and a highly sensitive optical detector, catering to the needs of long-term deployment and continuous ocean observation. It can operate stably for extended periods under typical conditions such as seawater corrosion and high hydrostatic pressure (maximum operating depth up to 6000m), enabling accurate detection of chlorophyll in the water.

[0097] like Figures 2-7 As shown: The connection component includes:

[0098] The first mounting groove 7 is formed on the side wall of the cover and is an annular groove.

[0099] The second mounting groove 8 is correspondingly opened on the inner side wall of the housing 1, and can communicate with the first mounting groove 7 during installation;

[0100] The first connecting hole 9 is opened on the side wall of the cover and communicates with the first mounting groove 7. The central axis of the first connecting hole 9 is perpendicular to the central axis of the first mounting groove 7.

[0101] The second connecting hole 10 is formed on the side wall of the housing 1 and communicates with the second mounting groove 8. The central axis of the second connecting hole 10 extends in the same direction as the central axis of the first connecting hole 9, and the second connecting hole 10 can communicate with the first mounting groove 7.

[0102] The first connector 11 can be simultaneously disposed in the first mounting groove 7 and the second mounting groove 8, and its sidewall can simultaneously and tightly abut against the inner wall of the first mounting groove 7 and the inner wall of the second mounting groove 8. One end of the first connector 11 can pass through the second connecting hole 10 and enter the first mounting groove 7 and the second mounting groove 8 from one side of the first connecting hole 9, and extend out from the first mounting groove 7 and the second mounting groove 8 on the other side of the first connecting hole 9, and converge with the other end at the first connecting hole 9.

[0103] The second connector 12 has one end that can pass through the second connecting hole 10 and enter the first connecting hole 9, pressing both ends of the first connector 11 into the first connecting hole 9 and threadedly connecting them to the first connecting hole 9. The other end can abut against the outer wall of the housing 1.

[0104] In this embodiment, the second mounting groove 8 and the first mounting groove 7 are in the same position, size and shape, and their cross-sections are both semicircular. The first connector 11 is a fishing line, the second connector 12 is a bolt, and the central axis of the first connecting hole 9 and the first mounting groove 7 are perpendicular and intersecting. The diameter of the first connecting hole 9 is larger than the width of the groove of the first mounting groove 7.

[0105] The working principle of the connecting component is as follows: During installation, the cover (first cover 4 or second cover 3) is first inserted into the storage space 2 at the end of the housing 1, so that the first mounting groove 7 opened on the side wall of the cover is aligned with the second mounting groove 8 on the inner side wall of the housing 1 in the axial direction, and at the same time, the first connecting hole 9 on the cover is aligned with the second connecting hole 10 on the housing 1 in the radial direction.

[0106] Then, the first connector 11 is inserted from one side of the second connecting hole 10, so that one end passes through the second connecting hole 10 and enters the annular cavity formed by the first mounting groove 7 and the second mounting groove 8. The first connector 11 circles around the annular cavity, and its two ends finally converge at the first connecting hole 9 from both sides.

[0107] Finally, screw the second connector 12 (such as a set screw) into the second connecting hole 10. Its front end enters the first connecting hole 9 and presses down on both ends of the first connector 11, forcing the first connector 11 to be tensioned within the annular cavity, so that its sidewalls simultaneously form a tight abutment with the inner walls of the first mounting groove 7 and the second mounting groove 8. Continue to tighten the second connector 12 until its head abuts against the outer wall of the housing 1 or sinks into the second connecting hole 10. At this point, the cover and the housing 1 are locked in both the axial and radial directions, and the sealing element 24 is compressed, achieving a sealed connection.

[0108] During disassembly, use a tool to loosen the second connector 12 by rotating it in the opposite direction, and remove it from the first connecting hole 9 and the second connecting hole 10 to release the clamping force on the first connector 11.

[0109] After removing the first connector 11, pull the cover outward along the axial direction to completely remove it from the housing 1, thus completing the disassembly. The entire disassembly process does not damage any structural components and does not harm the seal 24, and can be repeated multiple times.

[0110] In this embodiment, the first connector 11 is simultaneously located in the first mounting groove 7 on the cover and the second mounting groove 8 on the housing 1. When pressed by the second connector 12, it can simultaneously restrict the axial movement and radial rotation of the cover relative to the housing 1, resulting in high connection rigidity and strong vibration and impact resistance. After the first connector 11 is pressed, a uniform radial force is applied along the entire circumference, avoiding local stress concentration caused by traditional screw connections, which is beneficial for maintaining sealing performance over a long period of time. After the second connector 12 is screwed into the first connecting hole 9, it forms a threaded connection with the first connecting hole 9. At the same time, its front end presses against both ends of the first connector 11, forming a mechanical anti-loosening structure, which will not loosen on its own even under deep-sea high pressure and flow-induced vibration environments. The entire connection process does not rely on the thread engagement between the housing 1 and the cover (the thread is only used for the second connector 12 itself), thus avoiding the problem of traditional threaded connections seizing up after seawater corrosion. During disassembly, only one screw needs to be loosened to release the lock: the sealing is mainly undertaken by the independent sealing element 24, with the second connector 12 assisting in the sealing, while the connection is undertaken by this component, and the two functions are separated. Even when the seal 24 needs to be replaced, there is no need to damage the connection structure, significantly improving maintenance convenience.

[0111] like Figure 3 and Figure 5As shown: The channel includes an installation area channel 13 and a detection area channel 14. One end of the detection area channel 14 can communicate with the storage space 2, and the other end can communicate with the installation area channel 13. The other end of the installation area channel 13 has an opening formed on the outer end face of the first cover 4, which communicates with the external space of the shell 1.

[0112] The detection component also includes a lens 15 and a filter 16. The lens 15 is disposed in the mounting area channel 13 and is sealed to the mounting area channel 13, and can cover the opening formed on the outer end face of the mounting area channel 13 on the cover body.

[0113] The detector 5, the light source 6, and the filter 16 are all disposed in the detection area channel 14. The ends of the detector 5 and the light source 6 that are away from the lens 15 can extend into the detection area channel 14 and be electrically connected to the control component. The filter 16 is located between the detector 5 and the lens 15, and also between the light source 6 and the lens 15.

[0114] Lens 15 cannot extend beyond the end face of the cover. In this embodiment, lens 15 is flush with the end face of the cover, and lens 15 is a sapphire lens. This segmented channel design arranges the optical elements (light source 6, detector 5, filter 16) and the sealing window (lens 15) in channel segments of different diameters or depths, achieving decoupling of optical positioning and sealing functions. Lens 15 is independently sealed and installed, avoiding direct compression of precision components such as filter 16 or detector 5; filter 16 is located in the optical path of both light source 6 and detector 5, effectively suppressing stray light and excitation light crosstalk, and improving the signal-to-noise ratio of fluorescence detection. In addition, the rear ends of detector 5 and light source 6 extend outside the channel and are electrically connected to the control components, facilitating circuit board-level maintenance and signal debugging, and reducing the difficulty of overall assembly.

[0115] The filter 16 in the channel where the detector 5 is located is a 695nm narrowband filter, which allows chlorophyll a red fluorescence to pass through while suppressing blue-violet / blue / green excitation light and non-target fluorescence.

[0116] The light source 6 is an LED, and the detector is a 695 nm photodiode.

[0117] like Figure 7 As shown: The storage space 2 includes a connection area and a storage area 17. The portion of the housing 1 located in the connection area is connected to the cover. The storage area 17 is used to store control components.

[0118] The inner diameter of the connecting area on the housing 1 is larger than the inner diameter of the storage area 17 on the housing 1, and the connecting area and the storage area 17 are connected by the first abutting part 18.

[0119] The end of the cover that is away from the water can abut against the first abutment 18;

[0120] The cover is provided with a second abutment 19 in the circumferential direction. One end of the second abutment 19 is connected to the outer wall of the cover, and the other end extends away from the central axis of the cover. The lower end face of the second abutment 19 can abut tightly against the end face of the shell 1.

[0121] In this embodiment, the end of the second abutment 19 that is away from the housing 1 is flush with the cover, and the side wall of the second abutment 19 is flush with the outer side wall of the housing 1.

[0122] The first abutment part 18 and the second abutment part 19 can be provided independently or simultaneously, forming a multi-level axial positioning and sealing enhancement structure. The first abutment part 18 limits the maximum insertion depth of the cover, preventing excessive compression of the internal circuit board or seal 24; the second abutment part 19 utilizes the annular flange of the cover itself to form an end-face sealing fit with the end face of the housing 1, further improving the pressure resistance under high pressure conditions. When used in combination, the two can achieve dual protection of "radial sealing + end-face sealing", enabling the sensor to maintain airtightness even at a water depth of 6000 meters, which is significantly better than the reliability of a single O-ring sealing structure.

[0123] like Figure 5 and Figure 6 As shown: The connecting area is divided into a sealing area 20 and a joining area 21. The joining area 21 and the storage area 17 are located on both sides of the sealing area 20. The inner diameter of the housing 1 in the joining area 21, the sealing area 20 and the storage area 17 increases sequentially. The joining area 21 and the sealing area 20 are connected by a third abutment 29, and the sealing area 20 and the storage area 17 are connected by a first abutment 18.

[0124] A fourth abutment 22 is provided on the side wall of the cover, and the fourth abutment 22 abuts against the third abutment 29, and the two fit tightly together.

[0125] The second mounting groove 8 is disposed in the mating area 21, and at least one sealing component is disposed on the sealing area 20. The component includes a third mounting groove 23 and a sealing element 24. The third mounting groove 23 is opened on the outer side wall of the cover, and the sealing element 24 is disposed in the third mounting groove 23 and can closely abut against the inner side wall of the housing 1.

[0126] In this embodiment, the sealing element 24 is an O-ring. In addition, for ease of installation, an auxiliary part 31 is provided at the connection between the inner wall of the housing 1 and the opening of the housing 1. The auxiliary part 31 is inclined in this embodiment, which can be approximately understood as a chamfered form. That is, it extends inclinedly from the opening towards the central axis of the housing 1 and connects with the inner wall of the housing 1 in the joint area 21 to facilitate the entry of the cover.

[0127] This three-tiered, stepped inner diameter design creates a "fitting-sealing-storage" functional zone. The fitting area 21 is used to install connecting components, the sealing area 20 centrally houses multiple O-rings, and the storage area 17 accommodates the circuit board. The tight fit between the third abutment 29 and the fourth abutment 22 provides precise axial positioning, ensuring that the seal 24 is within the correct compression range. The multiple sealing components are arranged sequentially along the axial direction, ensuring that even if the outer seal 24 ages and fails during long-term use, the inner seal 24 can still maintain its protective capability, forming a redundant sealing mechanism. This structure is particularly suitable for long-term anchoring deployments, significantly reducing the risk of sensor damage due to seal failure.

[0128] like Figure 3 and Figure 6 As shown: The control component includes:

[0129] The first circuit board 25 is detachably connected to the first cover 4 via the third connector 26, and the first circuit board 25 can be electrically connected to the detection component.

[0130] The second circuit board 27 is located on both sides of the first cover 4. The second circuit board 27 is connected to the first circuit board 25 through the fourth connector 28, and the second circuit board 27 is electrically connected to the first circuit board 25 and the signal transmission component 30.

[0131] In this embodiment, both the third connector 26 and the fourth connector 28 are bolts and nuts.

[0132] The dual-circuit board layered design separates the front-end amplification and analog-to-digital conversion of the detection signal (first circuit board 25) from the data processing, storage, and communication (second circuit board 27). The first circuit board 25 is closely attached to the first cover 4, shortening the analog signal trace distance between it and the light source 6 and detector 5, effectively suppressing electromagnetic interference and signal attenuation. The second circuit board 27 is placed deep within the storage space 2, away from the heat-generating light source 6 and external water conduction, which is beneficial for thermal management. The two circuit boards are detachably connected by a fourth connector 28, facilitating individual replacement or upgrades of either circuit board and reducing maintenance costs. This architecture also supports customized front-ends with different channel configurations on the first circuit board 25, while using a standardized second circuit board 27, achieving both hardware platform universality and personalized parameter configuration.

[0133] In this embodiment, the signal transmission component 30 is a watertight connector.

[0134] A marine biochemical optical detection method includes the following steps:

[0135] I. Parameter Settings

[0136] 1.1) Light source parameter settings: Excitation wavelengths of LEDs are 435nm, 470nm, and 532nm;

[0137] 1.2) Detector parameter settings: Configure a 695nm narrowband filter for the detector receiving wavelength of 695nm;

[0138] 1.3) Sampling parameters: For each measurement cycle, set the light source to be off and the dark field sampling, the number of repeated pulses N, the outlier removal threshold, and the calibration curves for each parameter;

[0139] Three excitation LEDs at 435 nm, 470 nm, and 532 nm are used, all sharing a single 695 nm photodiode detection channel. The 695 nm channel receives only the main band of chlorophyll a red fluorescence through a composite filter, blocking direct and stray light from the three excitation lights.

[0140] 470 nm was set as the main excitation wavelength for chlorophyll quantification; 435 nm was set as the auxiliary excitation wavelength to enhance the response of low-concentration chlorophyll, determine the response of the blue-violet absorption band, and assist in correcting the bias of the single 470 nm channel; 532 nm was set as the auxiliary pigment excitation wavelength to obtain the 695 nm red fluorescence response after the energy transfer of auxiliary pigments such as phycoerythrin / phycobiliprotein to chlorophyll a.

[0141] The controller has a pre-stored three-wavelength chlorophyll calibration model, with the model inputs being S435→695, S470→695, and S532→695.

[0142] II. Data Acquisition

[0143] 2.1) Dark field sampling: With all light sources turned off, measure the dark field / ambient light value of the detector as the background subtraction reference for this cycle;

[0144] 2.2) Auxiliary sampling: Only the 435 nm LED is lit, and after stabilization, M ADC points are collected. This is repeated N times to obtain the S435→695 data parameters as auxiliary data. This data is not used as the final chlorophyll main value, but is used to help determine the strength of the chlorophyll absorption band, light path pollution, or differences in community composition.

[0145] A 435 nm LED is lit, and a 695 nm detector collects data from S435 to 695. The 435 nm wavelength has a strong excitation effect on the blue-violet absorption band of chlorophyll a, and can provide auxiliary fluorescence intensity under low concentration or weak signal conditions. It can also be used to determine the abnormal response caused by differences in algal pigment absorption, internal filtration effect, or channel contamination.

[0146] 2.3) Principal value sampling: The 435 nm LED was turned off, and after the afterglow wait, only the 470 nm LED was lit. N sets of S470→695 data parameters were collected as the quantitative principal data of chlorophyll a.

[0147] The 470 nm LED is lit, and the 695 nm detector acquires data from S470 to 695. 470 nm is a commonly used blue light excitation band in chlorophyll a fluorescence sensing, and it is preferred as the main channel for chlorophyll quantification, so as to output the main concentration value that is easier to compare with conventional chlorophyll a fluorescence data.

[0148] 2.4) Correction sampling: After turning off the 470 nm LED and waiting for afterglow, only the 532 nm LED is lit, and N sets of S532→695 data parameters are collected as correction data. This data reflects the response of algae containing auxiliary pigments such as phycoerythrin / phycobiliprotein to green light excitation, and is used for cyanobacterial sensitivity, algal community differences and calibration correction.

[0149] A 532 nm LED was illuminated, and a 695 nm detector collected data from S532 to 695. The 532 nm wavelength excites accessory pigments such as phycoerythrin and phycobiliproteins; some of the energy is transferred to chlorophyll a via the algal photosynthetic antenna system, producing red fluorescence near 695 nm. This data is used to identify differences in algal community composition, sensitivity of cyanobacteria / phycobiliprotein-containing groups, and chlorophyll calibration correction.

[0150] At least three sets of raw fluorescence data will be output for each measurement cycle: S435→695, S470→695, and S532→695.

[0151] All three wavelengths use the same detector, filter, and analog front-end; therefore, the differences between the different excitation wavelengths mainly stem from the fluorescence response in the water rather than detector differences. Each light source is illuminated independently in chronological order, without synchronous excitation.

[0152] III. Data Selection

[0153] 3.1) Preprocessing: Preprocess the data obtained from each parameter;

[0154] 3.1.1) Take the average or median of the M ADC points in the stable sampling window;

[0155] 3.1.2) Within one period, the average value of N sets of pulse data after filtering by median, extreme value removal average, or standard deviation threshold;

[0156] 3.1.3) Remove outliers caused by momentary obstruction from bubbles and floating particles, and by electrical noise;

[0157] 3.1.4) The effective signal is subtracted for dark field using S=ADC_on-ADC_dark.

[0158] 3.2) Dark field subtraction is performed on the effective signals of each channel to obtain F435, F470 and F532;

[0159] 3.3) Based on the data processed above, formulate calibration curves for each parameter and output the final effective values ​​of each parameter.

[0160] The basic output is obtained by calibrating the curve using F470 to obtain the main value of chlorophyll a;

[0161] When the F470 signal is in the linear range and R435 / 470 and R532 / 470 are in the normal calibration range, the three-wavelength weighted average value is directly output.

[0162] When F435 / F470 is significantly higher or lower, F435 is used to correct F470, and the corrected value is output.

[0163] In this embodiment, at least four columns of data are output, including F470, F435, F532 and the three-wavelength weighted average value corrected by F435.

[0164] In terms of processing logic, S470→695 is used as the primary chlorophyll value; R435→695 / S470→695 is used to determine the difference in blue-violet excitation response; and the contribution of auxiliary pigments is also used to determine the contribution. When the two ratios are within the normal calibration range, the main channel result is output; when the ratios deviate from the normal range, the chlorophyll output is adjusted according to the calibration model or a community / low confidence flag is added.

[0165] The effect of combining three wavelengths is that, without increasing the number of detectors, it obtains three types of information: primary chlorophyll fluorescence, blue-violet auxiliary response, and auxiliary pigment response, thereby improving the accuracy, repeatability, and adaptability of chlorophyll detection to differences in algal communities.

[0166] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0167] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A marine biochemical optical sensor, characterized in that, include: The housing (1) has a storage space (2) inside. The storage space (2) has a first opening at the lower end of the housing (1) and a second opening at the upper end of the housing (1) at both ends. The cover is detachably connected to the housing (1) via a connecting assembly and includes a first cover (4) and a second cover (3) capable of covering and sealing the first opening and the second opening to close the storage space (2). A signal transmission component (30) is disposed on the second cover (3) at the second opening; The detection component is disposed on the first cover (4) at the first opening, and the detection component is electrically connected to the signal transmission component (30) through the control component disposed in the storage space (2); The detection component includes a detector (5) and three light sources (6) for detecting chlorophyll information in the water body; The connection component includes: The first mounting groove (7) and the first connecting hole (9) are both set on the side wall of the cover and are interconnected. The second mounting groove (8) and the second connecting hole (10) are both provided on the side wall of the housing (1) and are interconnected. A first connector (11) that can simultaneously abut against the first mounting groove (7) and the second mounting groove (8), and whose two ends converge at the first connecting hole (9). A second connector (12) that can abut against the side wall of the housing (1) and can pass through the second connecting hole (10) to detachably install both ends of the first connector (11) in the first connecting hole (9).

2. The marine biochemical optical sensor according to claim 1, characterized in that, The first cover (4) has two channels, the three light sources (6) are located in one channel, and the detector (5) is located in the other channel.

3. A marine biochemical optical sensor according to claim 2, characterized in that, The receiving wavelength of the detector (5) is 695nm; The light source (6) is provided in three places, with excitation wavelengths of 435nm, 470nm and 532nm respectively. The light source (6) with an excitation wavelength of 435nm is used for auxiliary detection, the light source (6) with an excitation wavelength of 532nm is used for detection correction, and the light source (6) with an excitation wavelength of 470nm is used for main detection.

4. A marine biochemical optical sensor according to claim 2 or 3, characterized in that, The channel includes an installation area channel (13) and a detection area channel (14). One end of the detection area channel (14) can be connected to the storage space (2), and the other end is connected to the installation area channel (13). The other end of the installation area channel (13) has an opening formed on the outer end face of the first cover (4) and is connected to the external space of the shell (1). The detection component also includes a lens (15) and a filter (16). The lens (15) is disposed in the mounting area channel (13) and is sealed to the mounting area channel (13), and can cover the opening formed on the outer end face of the mounting area channel (13). The detector (5), light source (6) and filter (16) are all located in the detection area channel (14). The ends of the detector (5) and the light source (6) that are away from the lens (15) can extend into the detection area channel (14) and be electrically connected to the control component. The filter (16) is located between the detector (5) and the lens (15), and also between the light source (6) and the lens (15).

5. A marine biochemical optical sensor according to claim 3, characterized in that, The filter (16) in the channel where the detector (5) is located is a 695nm narrowband filter, which allows chlorophyll a red fluorescence to pass through while suppressing blue-violet / blue / green excitation light and non-target fluorescence. The light source (6) is an LED, and the detector (5) is a 695nm photodiode.

6. A marine biochemical optical sensor according to claim 1, 2, 3 or 5, characterized in that, The storage space (2) includes a connection area and a storage area (17). The portion of the housing (1) located in the connection area is connected to the cover. The storage area (17) is used to store control components. The inner diameter of the connecting area on the housing (1) is larger than the inner diameter of the storage area (17) on the housing (1), and the connecting area and the storage area (17) are connected by a first abutment (18); The end of the cover that is away from the water body can abut against the first abutment part (18); Alternatively, a second abutment (19) may be provided in the circumferential direction of the cover. One end of the second abutment (19) is connected to the outer wall of the cover, and the other end extends away from the central axis of the cover. The lower end face of the second abutment (19) can closely abut against the end face of the shell (1).

7. A marine biochemical optical detection method applicable to the marine biochemical optical sensor described in claim 1, characterized in that, Includes the following steps: I. Parameter Settings 1.1) Light source (6) parameter settings: excitation wavelengths of LEDs of 435nm, 470nm and 532nm respectively; 1.2) Detector (5) parameter settings: The detector (5) with a receiving wavelength of 695nm is configured with a 695nm narrowband filter; 1.3) Sampling parameters: For each measurement cycle, set the light source (6) to turn off dark field sampling, the number of repeated pulses N, the outlier removal threshold and the calibration curve of each parameter; II. Data Acquisition 2.1) Dark field sampling: Turn off all light sources (6), measure the dark field / ambient light value of detector (5) as the background subtraction reference for this cycle; 2.2) Auxiliary sampling: Only the 435nm LED is lit, and after stabilization, M ADC points are collected. This process is repeated N times to obtain the S435→695 data parameters, which are used as auxiliary data. 2.3) Principal value sampling: The 435nm LED is turned off, and after the afterglow wait, only the 470nm LED is lit. After stabilization, M ADC points are collected, and N sets of S470→695 data parameters are collected as the chlorophyll a quantitative principal data. 2.4) Correction sampling: Turn off the 470nm LED, wait for afterglow, and only turn on the 532nm LED. After stabilization, collect M ADC points and N sets of S532→695 data parameters as correction data. III. Data Selection 3.1) Preprocessing: Preprocess the data obtained from each parameter; 3.2) Dark field subtraction is performed on the effective signals of each channel; 3.3) Based on the data processed above, formulate calibration curves for each parameter and output the final effective values ​​of each parameter.

8. The marine biochemical optical detection method according to claim 7, characterized in that, In step 3.1), the specific content of the preprocessing is as follows: 3.1.1) Take the average or median of the data from the M ADC points in each stable sampling window; 3.1.2) Within one period, the average of N sets of pulse data is processed by taking the median, removing extreme values, or using the average value after standard deviation threshold filtering. The auxiliary data were processed by removing extreme values ​​and averaging the S435→695 method. The quantitative main data of chlorophyll a were processed by averaging the standard deviation threshold. The corrected data S532→695 were processed by taking the median. 3.1.3) Remove outliers caused by bubbles, momentary occlusion by floating particles, and electrical noise based on the outlier removal threshold; 3.1.4) The effective signals of each channel are subjected to dark field subtraction according to S=ADC_on-ADC_dark to obtain F435, F470 and F532.

9. A marine biochemical optical detection method according to claim 8, characterized in that, In step 3.3), the selection criteria for each parameter are as follows: The basic output is based on the chlorophyll a value obtained from the calibration curve of F470. When the F470 signal is in the linear range and R435 / 470 and R532 / 470 are in the normal calibration range, the three-wavelength weighted average value is directly output. When F435 / F470 is significantly higher or lower, F435 is used to correct F470, and the corrected value is output.

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