Microalgae density measurement system based on optical detection and microalgae density measurement and correction method

Abstract

The invention discloses a microalgae density measurement system based on optical detection and a microalgae density measurement and correction method, and the method comprises the following steps: transmitting known microalgae solutions with different densities by using a standard LED lighting device based on an optical conversion material, and obtaining real-time changing optical power behind the solutions by using a miniature photoelectric detector, meanwhile, the photo-generated current obtained by testing the optical power is displayed and stored by using a high-precision source meter; a light conversion material or an LED chip for excitation of the standard LED lighting device is changed according to needs, a light source is reassembled, and then the non-standard LED lighting device is adopted to test the density of the microalgae solution; then calculating and correcting the density of the microalgae solution tested under the non-standard light source condition by adopting a calibration formula; and finally, performing accuracy calculation on the microalgae density obtained by correction under different non-standard light source conditions, and comparing accuracy influence factors under different test conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of optical testing, and in particular relates to a microalgae density measurement system based on light detection and a microalgae density measurement and correction method. Background Art

[0002] In the field of microalgae cultivation, in order to accurately and quickly detect the content of microalgae particles, the current traditional detection methods include dry weight method, ultrasonic detection method, counting method and electrode method. The dry weight method is to place a certain volume of suspension in a high-speed centrifuge for solid-liquid centrifugal separation. After several washes, the separated precipitate is centrifuged again, and then the particles after centrifugation are dried at high temperature. Then the dried particles are placed in a constant weight and dry weighing bottle, the mass of the separated particles is weighed, and finally the content of the particles is calculated. The counting method is often used to detect the number of cells, using a cell counter or dyeing with methylene blue. This method requires observation and counting with a microscope, and the sample needs to be diluted many times, which may lead to large errors. The working principle of ultrasonic method for detecting concentration is that when the ultrasonic wave passes through the suspension, the particles absorb the sound wave, the ultrasonic energy is attenuated, the amplitude is reduced, and the sound intensity, sound velocity or sound resistance before and after the ultrasonic wave is incident will change. There is a certain relationship between the concentration and the change of the ultrasonic wave. According to this principle, the density of the suspended particles can be measured. However, such instruments are susceptible to changes in fermentation broth composition, bubbles, temperature changes and viscosity. The electrode method is a standard electrochemical detection method that uses changes in the dielectric constant between electrodes to measure the concentration of particles in the suspension. However, this method is usually used to detect the number of living cells and still has certain limitations for the detection of all types of granular suspended microalgae.

[0003] With the rapid development of optoelectronic technology, the application of photoelectric method in detecting the concentration of suspensions has become more and more extensive. In the development of optoelectronic technology, advanced light sources with good performance continue to emerge, such as light-emitting diodes (LEDs), infrared light-emitting diodes, lasers and infrared lasers. These light sources have stable working conditions and long lifespans. They can provide stable incident light for a long time during concentration detection, thereby simplifying the detection process of optical signals and greatly improving the accuracy of detection. In addition, the improvement of the quantum efficiency, light amplification effect, thermoelectric stability and other performance of the photodetector also provides a reliable guarantee for the accuracy of the photoelectric detection technology.

[0004] At present, the microalgae density detection technology based on photoelectric technology includes photometer detection, fiber optic detection and other methods. However, there are several limitations in the research on optical methods for measuring microalgae density: (1) Long test process. The traditional steps of testing microalgae density include sampling, detection, calculation, information transmission, information storage and other links. When testing a large number of samples, it is easy to cause data confusion and the process is complicated. (2) The light source has low adjustability. Researchers often use commercial light-emitting diodes, but rarely adjust or calibrate the illumination characteristics of the light source used for optical measurement. Factors such as the brightness, wavelength, light power, emission angle, and light color of the light source have not been fully considered. (3) Insufficient research on influencing factors. There is little in-depth research on the factors affecting the accuracy of microalgae density measurement, and the analysis of improving measurement accuracy is also insufficient. (4) Ignoring the difference in optical properties. The difference in optical properties between different microalgae species is easy to be ignored. Therefore, the existing evaluation methods may not be applicable to various test environments. (5) Limited culture density range. Many studies do not cover the range of commonly used culture densities of microalgae; instead, they are more likely to focus on one of the commonly used culture densities of microalgae and lack representativeness. Therefore, many aspects of microalgae density measurement have not been fully studied, such as the impact of different light wavelengths on the optical measurement results of specific microalgae species. In summary, the development of a flexible and reliable microalgae density test method is important for large-scale microalgae cultivation, real-time measurement and monitoring. Summary of the invention

[0005] The present invention provides a microalgae density measurement system based on light detection and a microalgae density measurement and correction method, which can solve the problem that the adjustability of the light source and the test accuracy are not considered in the microalgae density measurement method in the prior art. The method detects the change of the light power passing through the microalgae solution by a photodetector, and uses the photocurrent generated by the photodetector to evaluate the change of the microalgae density in real time, thereby simplifying the detection process; in addition, the present invention also adopts a newly proposed calibration method and calibration formula to calculate and correct the density of the microalgae solution tested under non-standard light source conditions, and evaluates the calculation accuracy; the present invention establishes a direct conversion relationship between the photocurrent and the microalgae density, and the test and calculation are simple and reliable, thereby ensuring the stability of long-term monitoring.

[0006] To solve the above problems, the technical solution provided by the present invention is as follows:

[0007] The embodiment of the present invention provides a microalgae density measurement system based on light detection, comprising a lifting platform (7), a rotating turntable (8) is arranged on the lifting platform (7), a transparent microalgae solution container (1) is arranged in the middle of the rotating turntable (8), and a first bracket (6-1) and a second bracket (6-2) are symmetrically arranged on both sides of the rotating turntable (8); an LED lighting device is arranged on the first bracket (6-1), and the LED lighting device comprises an LED chip (2), a reflective cup (4) connected to the LED chip (2), and a light conversion material layer (3) located on the light emitting surface of the reflective cup (4); the LED chip (2) is electrically connected to a direct current power supply (9); a photodetector (5) is arranged on the second bracket (6-2), the photodetector (5) is electrically connected to an active meter (10), and the source meter (10) is electrically connected to an information processor (11);

[0008] The microalgae solution container (1) is used to hold microalgae solutions of different densities and species; the LED chip (2) is used as an excitation light source for the light conversion material and to adjust the light brightness of the LED lighting device during testing; the light conversion material layer (3) is used to convert the short wavelength of the LED chip into a different long wavelength within the visible light range; the reflective cup (4) is used to collect the light generated by the LED chip and pass it through the light conversion material to excite the light conversion material layer (3) to emit light; the edge of the reflective cup (4) is used to fix the light conversion material layer (3); and the photodetector (5) is used to receive light emitted by the light source. The invention relates to a method for measuring the light signal of the microalgae solution container (1) by using a lifting platform (7) to adjust the vertical height at which the microalgae solution container (1) is placed during the test; the rotating turntable (8) is used to control the rotation angle of the microalgae solution container (1) and the LED lighting device relative to the photoelectric detector (5); the DC power supply (9) is used to adjust the parameters of the driving voltage and driving current of the LED chip (2); the source meter (10) is used to electrically connect the photoelectric detector (5) and to feed back the real-time photocurrent changes detected by the photoelectric detector (5); and the information processor (11) is used to obtain the information of the photocurrent obtained by the source meter (10) and to perform data analysis and calculation.

[0009] In an optional embodiment of the present invention, the LED chip (2) is any one of a short-wave light source of a deep ultraviolet LED, an ultraviolet LED, or a blue light LED; the power of the LED chip (2) is selected according to the thickness of the microalgae solution container (1) to be tested. If the thickness of the microalgae solution container (1) is relatively thick, a relatively high-power LED chip can be selected to emit light to ensure that the light has high penetration; if the thickness of the microalgae solution container (1) is relatively thin, a relatively low-power LED chip can be selected to emit light to ensure that the test light power is within the test range.

[0010] In an optional embodiment of the present invention, the material of the light conversion material layer (3) is any one of the light conversion materials of phosphor, quantum dots, perovskite, and organic dyes.

[0011] In an optional embodiment of the present invention, the reflective cup (4) is made of aluminum or acrylic.

[0012] In an optional embodiment of the present invention, the information processor (11) adopts an operating terminal device such as a computer or a tablet.

[0013] An embodiment of the present invention provides a method for measuring and correcting microalgae density based on light detection, which is implemented by a microalgae density measurement system based on light detection as in the above embodiment, and includes the following steps:

[0014] Step 1: characterize the various luminescent properties of the light conversion material and LED chip, perform biological characterization on the microalgae solution, and use traditional test methods to measure the parameters of microalgae morphology, microalgae solution density, and microalgae color in the microalgae solution; characterize the light response properties of the photodetector at different wavelengths; store all the test parameters in the information processor for subsequent retrieval;

[0015] Step 2, using a standard LED lighting device composed of a specific light conversion material and an LED chip to test the microalgae solution, obtain a real-time photocurrent, and perform analysis;

[0016] Step 3, using a non-standard LED lighting device composed of any light conversion material and LED chip to test the microalgae solution, obtain a real-time photocurrent, and perform analysis;

[0017] Step 4, using a calibration formula to calculate and correct the density of the microalgae solution tested under the non-standard LED lighting device conditions in step 3;

[0018] Step 5, evaluating the calculated density of the microalgae solution to obtain the accuracy under different test conditions.

[0019] In an optional embodiment of the present invention, step 2 specifically includes: selecting a fixed light conversion material and an LED chip, combining them to produce an LED lighting device, and defining the LED lighting device as a standard LED lighting device; using the standard LED lighting device to test marine microalgae samples of different concentrations, and obtaining photocurrent through a photodetector; performing linear regression analysis on photocurrent data obtained under test conditions of marine microalgae of different densities, and fitting the data to obtain a change trend of the photocurrent under conditions of different marine microalgae densities; analyzing the relationship between the change of the photocurrent and the marine microalgae density, and obtaining the following formula:

[0020] D M =α·P S (1); where D M is the density of marine microalgae, α is the proportionality coefficient, P S is the magnitude of the photocurrent;

[0021] Among them, the test conditions include: general conditions and specific conditions; the general conditions include: the detection system can operate normally and remain stable to ensure that the microalgae solution with unknown microalgae density is evenly distributed; the incident angle of the light source is kept unchanged during the test; the specific conditions include: visible light of different wavelengths, different types of light sources, different algae species, different optical paths and any one of detecting microalgae density distribution.

[0022] In an optional embodiment of the present invention, step 3 specifically includes: non-standard test link: since the LED lighting device based on light conversion materials has the characteristics of flexible regulation, the standard LED lighting device can be changed into a non-standard LED lighting device by changing the light conversion material and the LED chip, and the test of step 1 can be performed.

[0023] In an optional embodiment of the present invention, step 4 specifically includes: the non-standard LED lighting device is characterized in that the light conversion material and the LED chip are adjustable. Therefore, when the standard LED lighting device is changed to a non-standard LED lighting device, α and P in formula (1) are S The parameters will fluctuate, so it is necessary to recalibrate D through density correction. M With P S The calibration takes into account the photoconversion efficiency of different photoconversion materials, the effect of color change on the photosensitivity of the photodetector, and the absorption of different colors by microalgae; in this case, the calibrated photocurrent is defined as P C The ratio of the light conversion efficiency of the new light conversion material to the old light conversion material is LE, and the ratio of the sensitivity of the photodetector to the new light conversion material to the sensitivity of the photodetector to the old light conversion material is S R The light absorption rate of microalgae under the old light conversion material is A S The light absorption rate of microalgae under the old light conversion material is A C ; The above factors are used to calibrate the photocurrent P C To ensure that the calibrated photocurrent P C With the original photocurrent P S Consistent with D M Maintain clear relevance;

[0024] Calibrated photocurrent P C This can be calculated using the following calibration formula:

[0025] P C =P S LE S R ·(1-A C ) / (1-A S ) (2);

[0026] Formula (2) takes into account all changes to the microalgae solution and the photodetector in the process of replacing the non-standard standard LED lighting device; therefore, formula (2) is universal and can be applied not only to changes in different light conversion materials, but also to use under conditions of different LED chips; this adaptability is due to the fact that any changes that may be caused by changes in light conversion materials or LED chips have been taken into account in the calculation of LE; therefore, formula (2) ensures that the system can adapt to different configurations while maintaining the accuracy of density measurement;

[0027] Calibrated microalgae density D MC It is described by the following formula (3), which includes the calibrated photocurrent P C , D MC =α·P C (3).

[0028] In an optional embodiment of the present invention, step 5 specifically includes: accuracy calculation and analysis link: in order to verify that D M The accuracy of the test can be calculated using the following equation in the accuracy evaluation step 5. C ,

[0029] Compared with the prior art, the embodiments of the present invention provide a microalgae density measurement system and a microalgae density measurement and correction method based on light detection, which have the following beneficial effects:

[0030] (1) The present invention proposes a simple test method for the density of marine microalgae based on optical signals. The method uses light as a medium, is contactless, environmentally friendly, and does not require frequent sampling. The density of the microalgae solution can be monitored at different parts of the microalgae cultivation container by only using a mobile testing device, thus avoiding the contamination of the microalgae solution caused by frequent sampling.

[0031] (2) The present invention can directly use a cheap LED lighting device as a light source and use the photocurrent obtained by the photodetector test as the monitoring object. It has the advantages of being simple and easy to test. The test system is portable and can be widely used in signal testing in various occasions.

[0032] (3) The present invention assembles the light source required for the microalgae density test by combining light conversion materials with reflective cups and LED chips. It has flexible adjustability in the microalgae density test, and can select a suitable combination from any assembled LED lighting device for testing and result correction. Compared with the traditional single LED lighting device, the present invention is more suitable for microalgae density research in various occasions.

[0033] (4) The present invention proposes a method for correcting the microalgae density measurement results under non-standard LED lighting conditions. This method can ensure that the measured microalgae density still maintains a high accuracy rate under different light conversion materials and LED chip combinations.

[0034] (5) The present invention proposes a method for calculating the accuracy of corrected microalgae density, and the applicability of the present invention is evaluated by calculating the accuracy. The present invention has certain commercial value, and can support the technical needs in the fields of marine sewage detection, microalgae solution culture monitoring, and breakthroughs in key technologies of marine visible light sensing. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 A schematic diagram of the structure of a microalgae density measurement system based on light detection provided in an embodiment of the present application.

[0037] Figure 2 This is a flowchart of an implementation method of a microalgae density measurement and correction method based on light detection provided in an embodiment of the present application.

[0038] Figure 3 This is a photocurrent distribution diagram obtained under 7 different angle test conditions for a microalgae density measurement and correction method based on light detection provided in an embodiment of the present application.

[0039] Figure 4 A graph of photocurrent changes under different microalgae density conditions obtained by a microalgae density measurement and correction method based on light detection provided in an embodiment of the present application.

[0040] Figure 5 A method for measuring and correcting microalgae density based on light detection is provided in an embodiment of the present application to calculate the accuracy of green algae density under different voltages.

[0041] Figure 6 A method for measuring and correcting microalgae density based on light detection is provided in an embodiment of the present application to calculate the accuracy of green algae density at different test angles.

[0042] Figure 7 A method for measuring and correcting microalgae density based on light detection is provided in an embodiment of the present application to calculate the accuracy of golden algae density under different voltages.

[0043] Figure 8 A method for measuring and correcting microalgae density based on light detection is provided in an embodiment of the present application to calculate the accuracy of golden algae density at different test angles.

[0044] Fig. 9 The present invention provides a method for measuring and correcting microalgae density based on light detection, and provides an accuracy rate of green algae density calculation under different LED chip excitation conditions.

[0045] Fig.10 The present invention provides a method for measuring and correcting microalgae density based on light detection, and provides an accuracy rate of calculating the density of golden algae under different LED chip excitation conditions.

[0046] Fig.11 The accuracy of green algae density calculation under orange light and different LED chip excitation conditions is provided in a microalgae density measurement and correction method based on light detection provided in an embodiment of the present application.

[0047] Fig.12 The accuracy of green algae density calculation under different LED chip excitation conditions using red light is provided in a microalgae density measurement and correction method based on light detection provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0049] like Figure 1 As shown, the embodiment of the present invention provides a microalgae density measurement system based on light detection, including a lifting platform 7, a rotating turntable 8 is arranged on the lifting platform 7, a transparent microalgae solution container 1 is arranged in the middle of the rotating turntable 8, and a first bracket 6-1 and a second bracket 6-2 are symmetrically arranged on both sides of the rotating turntable 8, that is, the first bracket 6-1 is arranged on the left side of the microalgae solution container 1, and the second bracket 6-2 is arranged on the right side of the microalgae solution container 1. An LED lighting device is arranged on the first bracket (6-1), and the LED lighting device includes an LED chip 2, a reflective cup 4 connected to the LED chip 2, and a light conversion material layer 3 located on the light emitting surface of the reflective cup 4; the LED chip 2, the light conversion material 3, and the reflective cup 4 together form an LED lighting device with adjustable color and adjustable brightness. The LED chip 2 is electrically connected to a DC power supply 9; a photodetector 5 is arranged on the second bracket 6-2, the photodetector 5 is electrically connected to an active meter 10, and the source meter 10 is electrically connected to an information processor 11.

[0050] Among them, the microalgae solution container 1 is used to hold microalgae solutions of different densities and different varieties; the LED chip 2 is used as an excitation light source for the light conversion material and to adjust the luminous brightness of the LED lighting device during the test; the light conversion material layer 3 is used to convert the short wavelength of the LED chip into different long wavelengths within the visible light range; the reflective cup 4 is used to collect the light generated by the LED chip and pass through the light conversion material to excite the light conversion material layer 3 to emit light; the edge of the reflective cup 4 is used to fix the light conversion material layer 3; the photodetector 5 is used to receive the light signal emitted by the light source; the lifting platform 7 is used to adjust the vertical height of the microalgae solution container 1 during the test; the rotating turntable 8 is used to control the rotation angle of the microalgae solution container 1 and the LED lighting device relative to the photodetector 5; the DC power supply 9 is used to adjust the parameters of the driving voltage and driving current of the LED chip 2; the source meter 10 is used to electrically connect the photodetector 5 and feedback the real-time photocurrent changes of the photodetector 5; the information processor 11 is used to obtain the information of the photocurrent obtained by the source meter 10 and perform data analysis and calculation. The first bracket 6-1, the lifting platform 7, the rotating turntable 8 and the second bracket 6-2 can be fixed on the optical platform for experimental testing.

[0051] The LED chip 2 is any one of the short-wave light sources of deep ultraviolet LED, ultraviolet LED, and blue light LED; the power of the LED chip 2 is selected according to the thickness of the tested microalgae solution container 1. If the thickness of the microalgae solution container 1 is thicker, a higher-power LED chip can be selected to emit light to ensure that the light has high penetration; if the thickness of the microalgae solution container 1 is thinner, a lower-power LED chip can be selected to emit light to ensure that the test light power is within the test range. The material of the light conversion material layer 3 is any one of the light conversion materials of phosphors, quantum dots, perovskites, and organic dyes, but considering the film-forming characteristics, luminescence characteristics, and response characteristics of the light conversion material, in the present invention, stable, narrow-spectrum, and color-adjustable quantum dots are preferably used as light conversion materials; preferably, the thickness of the light conversion material is thicker to ensure that it only transmits long-wavelength monochromatic light after light conversion. The reflective cup 4 is made of aluminum or acrylic. The photodetector 5 can be a PIN or APD diode, wherein the APD diode has a higher sensitivity and is suitable for fast response test scenarios; the source meter 10 is a high-precision source meter, so it can test the photocurrent change of the picoampere level, and has a higher applicability to the test of different microalgae densities. The information processor 11 is an operating terminal device using a computer or a tablet.

[0052] In the specific implementation process, the LED chip 2 is fixed on the substrate, the reflective cup 4 is fixed on the LED chip 2, and the light conversion material layer 3 is fixed on the edge of the reflective cup 4. The LED chip 2, the light conversion material layer 3, and the reflective cup 4 are assembled together into an LED lighting device and fixed with the first bracket 6-1. The microalgae solution container 1 is placed on the lifting platform 7. When it is necessary to test data at different angles, a rotating turntable 8 can be placed between the microalgae solution container 1 and the lifting platform 7 to control the rotation of the LED lighting device and the microalgae solution container 1. The photodetector 5 is fixed on the second bracket 6-2, and the LED lighting device, the microalgae solution container 1, and the photodetector 5 are placed at the same horizontal height. The LED lighting device is aimed at the microalgae solution container 1, and the photodetector 5 receives the light signal emitted by the LED lighting device. The DC power supply 9 is connected to the positive and negative electrodes of the LED chip 2 to excite the LED chip 2 to emit light. The short-wavelength light emitted by the LED chip 2 is collected by the reflective cup 4, passes through the light conversion material layer 3, and converts the short-wavelength light into long-wavelength light. The converted light passes through the microalgae solution container 1 and reaches the photodetector 5. The photodetector 5 is connected to the source meter 10, and the source meter 10 displays and captures the photocurrent captured by the photodetector 5 in real time. The source meter 10 stores the photocurrent data and transfers it to the information processor 11 through the data line. Finally, the information processor 11 processes the photocurrent signal and obtains the density of the microalgae solution and the test accuracy through calculation.

[0053] In this embodiment, the light conversion material layer 3 is in the form of a thin sheet, which is convenient for light to pass through the light conversion material. The thickness of the light conversion material layer is usually about 3 mm, which ensures a certain light transmittance on the one hand, and ensures that the color purity of the light emitted through the light conversion material is high on the other hand. At the same time, the selection of light conversion materials needs to consider their optical properties such as light color, quantum efficiency, and light power, as well as their conversion rate and related response speed in the light conversion process and other properties related to detection and sensing.

[0054] Among the various light conversion materials used for lighting and display, such as commercial phosphors, organic dyes, perovskites, carbon dots, quantum dots, etc., quantum dot materials with high quantum efficiency, good monochromaticity, stable luminescence and fast modulation rate can be selected; taking cadmium selenide quantum dots as an example, it can produce most of the luminescent wavelengths in the visible light range under the excitation of blue light or ultraviolet light, and can achieve stable luminescence under high temperature conditions, which meets the requirements of realizing multiple different light conversion wavelengths to test the density of microalgae in this embodiment.

[0055] The use of quantum dots as light conversion materials plays a great supporting role in achieving its effects. Compared with other light conversion materials, the technical advantages of quantum dots include: 1. The luminescence peak of quantum dots is narrow, and the half-peak width ranges from about 20 nanometers to 40 nanometers, which helps to avoid the impact of inconsistent absorption coefficients of different bands in microalgae solutions on the experiment; 2. The internal quantum yield of quantum dots can be as high as 90%, with high luminescence intensity, thereby ensuring the stability of the total luminescence intensity; 3. The response speed of quantum dots is higher than that of ordinary commercial phosphors. Their fluorescence lifetime is usually on the order of 10 nanoseconds, while the fluorescence lifetime of commercial phosphors is as long as microseconds, which limits their response speed in light detection. Therefore, when using quantum dots for testing, the test requirements of rapid response can be met; 4. The luminescent color of quantum dots can be conveniently adjusted by controlling the size of quantum dots, the proportion of elements, etc. Therefore, in the experiment, continuously changing monochromatic light can be used to test the density of microalgae, and this continuously changing test effect cannot be achieved with traditional discrete luminescent peak semiconductor devices such as laser diodes and high-power light-emitting diodes; 5. The luminescent properties of quantum dots are relatively stable in a water-oxygen environment and can withstand high temperatures. They can be used with high-power LEDs and lasers to produce stable light output, thereby supporting the implementation of the experiment; 6. Compared with materials such as perovskites that have high requirements for non-polar environments, their film-forming properties are poor, and the manufacturing process of quantum dot membranes made of silicone can support quantum dots to be made into various flexible shapes to meet the needs of co-packaging with high-power light-emitting diodes in experiments.

[0056] The embodiment of the present invention provides a method for measuring and correcting microalgae density based on light detection, which is implemented by a microalgae density measurement system based on light detection as in the above embodiment. The method comprises: using a standard LED lighting device based on light conversion material to penetrate known microalgae solutions of different densities, and using a micro photodetector behind the solution to obtain real-time changing light power, and using a high-precision source meter to display and store the photocurrent obtained by testing the light power; changing the light conversion material or the excitation LED chip of the standard LED lighting device as needed, reassembling the light source, and then using the non-standard LED lighting device to test the density of the microalgae solution; then using the proposed calibration method and calibration formula to calculate and correct the density of the microalgae solution tested under non-standard light source conditions; finally, calculating the accuracy of the microalgae density corrected under different non-standard light source conditions, and comparing the accuracy influencing factors under different test conditions; the present invention uses a low-cost method to monitor the change of microalgae density, simplifies the test process, and at the same time, the present invention can also predict the microalgae density obtained by testing with different combinations of light sources, thereby improving the applicability of different light sources as test light sources.

[0057] Specifically, a method for measuring and correcting microalgae density based on light detection includes the following steps:

[0058] Step 1: characterize the various luminescent properties of the light conversion material and LED chip, perform biological characterization on the microalgae solution, and use traditional test methods to measure the parameters of microalgae morphology, microalgae solution density, and microalgae color in the microalgae solution; characterize the light response properties of the photodetector at different wavelengths; store all the test parameters in the information processor for subsequent retrieval;

[0059] Step 2, using a standard LED lighting device composed of a specific light conversion material and an LED chip to test the microalgae solution, obtain a real-time photocurrent, and perform analysis;

[0060] Step 3, using a non-standard LED lighting device composed of any light conversion material and LED chip to test the microalgae solution, obtain a real-time photocurrent, and perform analysis;

[0061] Step 4, using a calibration formula to calculate and correct the density of the microalgae solution tested under the non-standard LED lighting device conditions in step 3;

[0062] Step 5, evaluating the calculated density of the microalgae solution to obtain the accuracy under different test conditions.

[0063] Step 1 specifically includes: Characterization link: select cadmium selenide quantum dots as the light conversion material, and mix the cadmium selenide quantum dots with the silica gel solution; through the conventional method of high-temperature curing, cooling, and demolding, make the green, orange, and red cadmium selenide quantum dots into a 3 mm light conversion material layer 3 membrane for light conversion. Prepare LED chips with luminous wavelengths of 273nm, 305nm, 274nm, 405nm, and 450nm respectively. The luminous range covers short wavelengths such as deep ultraviolet, ultraviolet, and blue light, which are used to test the light conversion effects of different luminous wavelengths on cadmium selenide quantum dot membranes. Characterize the luminous performance of the above-mentioned quantum dot membranes, and measure the luminous spectrum, luminous peak wavelength, half-peak width, and light conversion efficiency of the light conversion material under different excitation light sources.

[0064] The luminous performance of the LED chip was characterized, and the parameters such as the luminous spectrum, peak wavelength, half-peak width, and luminous power of the LED chip under the working voltage were measured. Two microalgae solutions were biologically characterized, namely green algae and golden algae with different colors. The traditional test method was used to measure the parameters such as the morphology of microalgae, the density of microalgae solution, and the color of microalgae in the microalgae solution. A PIN diode was used as a photodetector to characterize the light response properties of the photodetector at different wavelengths from 300nm to 800nm. A computer was used as an information processor, and all the parameters obtained from the test were stored in the information processor for subsequent retrieval.

[0065] Step 2 specifically includes: standard test link: select a fixed light conversion material and LED chip, combine to produce an LED lighting device, and define the LED lighting device as a standard LED lighting device; use the standard LED lighting device to test marine microalgae samples of different concentrations, and obtain photocurrent through a photodetector; perform linear regression analysis on the photocurrent data obtained under the test conditions of marine microalgae of different densities, and fit the data to obtain the change trend of the photocurrent under different marine microalgae densities; analyze the relationship between the change of photocurrent and the density of marine microalgae, and obtain the following formula:

[0066] D M =α·P S (1); where D M is the density of marine microalgae, α is the proportionality coefficient, P S is the magnitude of the photocurrent.

[0067] Among them, the test conditions include: general conditions and specific conditions; the general conditions include: the detection system can operate normally and remain stable to ensure that the microalgae solution with unknown microalgae density is evenly distributed; the incident angle of the light source is kept unchanged during the test; the specific conditions include: visible light of different wavelengths, different types of light sources, different algae species, different optical paths and any one of detecting microalgae density distribution.

[0068] In this embodiment, a green quantum dot film and a 450nm blue LED chip are selected to form an LED lighting device, and the LED lighting device is defined as a standard LED lighting device. The density of the standard LED lighting device is 2.04×10 8 , 3.06×10 8 4.09×10 8 , 5.11×10 8 ,8.17×10 8 The green algae samples with densities of 1.20×10 9 , 3.45×10 9 4.79×10 9 , 5.98×10 9 , 9.57×10 9 The golden algae samples were tested at 1000 μg / L, and the corresponding photocurrent was obtained through the photodetector. The photocurrent data obtained under different densities of marine microalgae were subjected to linear regression analysis, and the data were fitted to obtain the changing trend of the photocurrent under different marine microalgae densities.

[0069] Figure 3 The photoelectric detector provided in this embodiment has a test angle of -40 degrees to 40 degrees and a test density of 2.04×10 8 , 3.06×108 4.09×10 8 , 5.11×10 8 ,8.17×10 8 The photocurrent distribution diagram obtained from the green algae solution of 1000 μl / L. The distribution of photocurrent presents a dome-shaped distribution centered at an angle of 0 degrees. Among them, the orange light with the highest luminous efficiency shows the highest photocurrent at any test angle, while the red light with the lowest luminous efficiency shows the lowest photocurrent. When light passes through the microalgae solution instead of air, the photocurrent decreases, which is due to the Figure 2 It can be seen from the comparison between the solid and dashed curves that the increase in the receiving angle significantly reduces the photocurrent obtained by the photodetector, which indicates that the receiving angle has an important influence on the measurement of microalgae density.

[0070] Figure 4 The test density provided in this embodiment is 2.04×10 8 , 3.06×10 8 4.09×10 8 , 5.11×10 8 ,8.17×10 8 When the green algae solution of 1000 micrograms / liter is matched with a green quantum dot film and a 450nm blue LED to form a standard LED lighting device, the photocurrent change trend and its fitting diagram under the conditions of LED driving voltage of 3.0V, 3.2V, and 3.5V are obtained. The results show that under different LED driving voltages, the relationship between the tested photocurrent and the microalgae density is linear, that is, the photocurrent can better reflect the changes in the microalgae density and establish a relationship with the real-time changes in the microalgae density.

[0071] Step 3 specifically includes: Non-standard test phase: Since LED lighting devices based on light conversion materials have the characteristics of flexible regulation, the standard LED lighting device can be changed into a non-standard LED lighting device by changing the light conversion material and the LED chip, and the test of step 1 can be carried out.

[0072] In this embodiment, since the LED lighting device based on the light conversion material has the characteristics of flexible regulation, the standard LED lighting device can be changed into a non-standard LED lighting device by changing the light conversion material and the LED chip, and the test of step 1 is performed. In step 3, the green light quantum dot film is changed into an orange or red quantum dot film, and the 450nm blue light LED chip is changed into a 273nm, 305nm, 274nm, 405nm deep ultraviolet and ultraviolet chip, and the test of step 2 is repeated to obtain the photocurrent P S .

[0073] Step 4 specifically includes: Correction link: The characteristics of non-standard LED lighting devices are that the light conversion material and LED chip are adjustable. Therefore, when the standard LED lighting device is changed to a non-standard LED lighting device, α and P in formula (1) are S The parameters will fluctuate, so it is necessary to recalibrate D through density correction. M With P S The calibration takes into account the photoconversion efficiency of different photoconversion materials, the effect of color change on the photosensitivity of the photodetector, and the absorption of different colors by microalgae; in this case, the calibrated photocurrent is defined as P C The ratio of the light conversion efficiency of the new light conversion material to the old light conversion material is LE, and the ratio of the sensitivity of the photodetector to the new light conversion material to the sensitivity of the photodetector to the old light conversion material is S R The light absorption rate of microalgae under the old light conversion material is A S The light absorption rate of microalgae under the old light conversion material is A C ; The above factors are used to calibrate the photocurrent P C To ensure that the calibrated photocurrent P C With the original photocurrent P S Consistent with D M Maintain clear relevance;

[0074] Calibrated photocurrent P C This can be calculated using the following calibration formula:

[0075] P C =P S LE S R ·(1-A C ) / (1-A S ) (2);

[0076] Formula (2) takes into account all changes to the microalgae solution and the photodetector that occur during the replacement of a non-standard LED lighting device; therefore, formula (2) is universal and can be applied not only to changes in different light conversion materials, but also to use under conditions of different LED chips; this adaptability is due to the fact that any changes that may be caused by changes in light conversion materials or LED chips have been taken into account in the calculation of LE; therefore, formula (2) ensures that the system can adapt to different configurations while maintaining the accuracy of density measurement.

[0077] Calibrated microalgae density D MC It can be described by the following formula (3), which includes the calibrated photocurrent P C , D MC =α·P C (3).

[0078] Step 5 specifically includes: Accuracy calculation and analysis: In order to verify the accuracy of the LED lighting device after using the non-standard standard LED lighting device M The accuracy of the test can be calculated using the following equation in the accuracy evaluation step 5. C ,

[0079] In this embodiment, eight aspects of the factors affecting the accuracy are analyzed.

[0080] like Figure 5 As shown in the figure, the green algae solution was selected as the observation object, and the standard LED lighting device composed of a green quantum dot film and a 450nm blue LED chip was used for testing. The calculation accuracy of the microalgae density of the non-standard LED lighting device composed of a corrected red quantum dot film and a 450nm blue LED chip under the above standard test conditions was analyzed under the conditions of LED chip driving voltage of 3.0V, 3.2V, and 3.5V. Figure 5 The average accuracy is higher than 0.93.

[0081] like Figure 6 As shown in the figure, the green algae solution was selected as the observation object, and the standard LED lighting device composed of a green quantum dot film and a 450nm blue LED chip was used for testing. The calculation accuracy of the microalgae density of the non-standard LED lighting device composed of a corrected red quantum dot film and a 450nm blue LED chip under the above standard test conditions was analyzed under the conditions of the photodetector receiving angle of 10 degrees, 20 degrees, and 30 degrees. The photodetector receiving angle is defined as the angle between the vertical line of the photodetector receiving interface and the light emitting angle of the LED chip. Figure 6 The average accuracy is higher than 0.87.

[0082] like Figure 7 As shown in the figure, golden algae solution was selected as the observation object, and a standard LED lighting device consisting of a green quantum dot film and a 450nm blue LED chip was used for testing. The calculation accuracy of microalgae density of a non-standard LED lighting device composed of a corrected red quantum dot film and a 450nm blue LED chip under the above standard test conditions was analyzed when the LED chip driving voltage was 3.0V, 3.2V, and 3.5V. Figure 7 The average accuracy is higher than 0.90.

[0083] like Figure 8As shown in the figure, golden algae solution was selected as the observation object, and a standard LED lighting device consisting of a green quantum dot film and a 450nm blue LED chip was used for testing. The accuracy of microalgae density calculation of a non-standard LED lighting device consisting of a corrected red quantum dot film and a 450nm blue LED chip under the above standard test conditions was analyzed under the conditions of a photodetector receiving angle of 10 degrees, 20 degrees, and 30 degrees. Figure 8 The average accuracy is higher than 0.96.

[0084] like Fig. 9 As shown in the figure, the green algae solution was selected as the observation object, and the green quantum dot film and 273nm, 305nm, 274nm, 405nm deep ultraviolet and ultraviolet LED chips were used to form a standard LED lighting device for testing. The calculation accuracy of the microalgae density was analyzed after the orange quantum dot film and 273nm, 305nm, 274nm, 405nm deep ultraviolet and ultraviolet LED chips were corrected to form a non-standard LED lighting device under the above standard test conditions. Fig. 9 The average accuracy is higher than 0.93.

[0085] like Fig.10 As shown in the figure, golden algae solution was selected as the observation object, and the green quantum dot film and 273nm, 305nm, 274nm, 405nm deep ultraviolet and ultraviolet LED chips were used to form a standard LED lighting device for testing. The calculation accuracy of microalgae density was analyzed after correcting the orange quantum dot film and 273nm, 305nm, 274nm, 405nm deep ultraviolet and ultraviolet LED chips to form a non-standard LED lighting device under the above standard test conditions. Fig.10 The average accuracy is higher than 0.91.

[0086] like Fig.11 As shown in the figure, the green algae solution was selected as the observation object, and the standard LED lighting device composed of orange quantum dot film and 400nm ultraviolet LED chip was used for testing. The accuracy of the non-standard LED lighting device composed of 273nm, 305nm, 274nm, and 405nm deep ultraviolet and ultraviolet LED chips in the calculation of microalgae density was analyzed under the above standard test conditions. Fig.11 The average accuracy is higher than 0.94.

[0087] like Fig.12As shown in the figure, the green algae solution was selected as the observation object, and the standard LED lighting device composed of a red quantum dot film and a 400nm ultraviolet LED chip was used for testing. The accuracy of the non-standard LED lighting device composed of a corrected red quantum dot film and 273nm, 305nm, 274nm, and 405nm deep ultraviolet and ultraviolet LED chips in the calculation of microalgae density was analyzed under the above standard test conditions. Fig.12 The average accuracy is higher than 0.90.

[0088] Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention. In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed.

[0089] The technical effects and advantages of the present invention are as follows: (1) Technically, the present invention uses conventional quantum dots, phosphors and other materials to prepare photoconversion materials with the support of existing technologies, and has the characteristics of high stability and easy preparation. (2) Technically, the present invention uses photocurrent as the monitoring object for feedback of microalgae density, which has the advantages of simple operation and high accuracy. Photocurrent and optical power are linearly positively correlated, and optical power is affected by the real-time density of microalgae. Therefore, photocurrent can directly reflect the dynamic changes of microalgae density without sampling, and observation is convenient and accurate. (3) In theory, this embodiment proposes a five-step implementation method. After characterizing the photoconversion material, LED chip, microalgae solution, etc., the photocurrent under different microalgae density conditions is tested under the conditions of a standard LED lighting device, and the photocurrent obtained under the conditions of a non-standard LED lighting device is corrected to derive and calculate the microalgae density, and finally calculate the accuracy of the present invention under different conditions. (4) In theory, this embodiment proposes a correction algorithm, which uses the photocurrent obtained under the condition of a standard LED lighting device to correct the photocurrent obtained under the condition of a non-standard LED lighting device, thereby calculating the density of microalgae under the condition of a non-standard LED lighting device. (5) In theory, this embodiment proposes an algorithm for calculating the accuracy of the microalgae density calculated by the present invention, and evaluating the universality of the present invention under conditions such as different LED chip driving voltages, photodetector receiving angles, light conversion material types, and LED chip types. (6) The present invention is technically feasible, and after the technology of the present invention matures, it can be used for marine environment monitoring; under outdoor test conditions, all test instruments involved in the present invention can be used for underwater detection after being waterproofed; (7) The function of the present invention is not only suitable for monitoring the density of a single microalgae species, but also for monitoring the density of multiple microalgae;

[0090] In addition, the following important aspects are also provided as auxiliary evidence for the novelty of the present invention:

[0091] The expected benefits and commercial value of the present invention after transformation are as follows: a. In the treatment of marine sewage, it is usually necessary to analyze the composition and characteristics of the suspended microalgae in the marine sewage sample suspension. By combining the correlation between the microalgae spectrum, scattering characteristics, transmission characteristics, etc. and the microalgae concentration and composition, the seawater quality can be effectively evaluated from the perspective of its optical properties. b. At present, the cultivation of functional microalgae has occupied a certain market share nationwide. At the same time, the cultivation and monitoring of microalgae are also developing in the direction of intelligent suspension solution monitoring and evaluation. The microalgae optical property evaluation mechanism proposed in the present invention can provide convenient technical support for this process. c. The current key technical bottleneck of marine visible light communication is that the transmission distance is easily limited by the water quality characteristics. Therefore, by evaluating the optical properties of the microalgae suspended seawater solution, the communication quality of underwater visible light communication under different water quality conditions can be dynamically monitored, which plays an important role in improving the communication rate and signal-to-noise ratio of marine visible light communication. In summary, whether from the aspects of marine sewage treatment, microalgae solution cultivation monitoring, or breakthroughs in key technologies of marine visible light communication, the present invention can effectively meet the technical needs;

[0092] Current research mainly focuses on the fields of microscopic measurement of microalgae density and remote sensing measurement of microalgae distribution density. There are few studies on measuring microalgae density by optical methods under near-field light field distribution conditions. Compared with the traditional microalgae density test method with multiple links such as microalgae sample collection, testing, calculation, and storage, the present invention has the characteristics of simplicity, high efficiency, and flexible light source replacement when monitoring microalgae density;

[0093] Whether the technical solution of the present invention solves the current technical problem: People have always hoped to obtain a reliable marine microalgae density monitoring device suitable for different test light sources, which can be used in the fields of seawater monitoring, microalgae cultivation monitoring, etc. In the present invention, this problem is solved.

[0094] Whether the technical solution of the present invention overcomes technical prejudice: Traditionally, the density measurement of microalgae relies on specific instruments such as microscopes and photometers. However, the present invention proposes a portable and flexibly assembled microalgae density measurement device and method, which can adjust the test distance and test angle according to the thickness of the microalgae solution container, and has a more complete test system compared with the existing methods.

[0095] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A microalgae density measurement system based on light detection, characterized in that: The invention comprises a lifting platform (7), a rotating turntable (8) is arranged on the lifting platform (7), a transparent microalgae solution container (1) is arranged in the middle of the rotating turntable (8), and a first bracket (6-1) and a second bracket (6-2) are symmetrically arranged on both sides of the rotating turntable (8); an LED lighting device is arranged on the first bracket (6-1), and the LED lighting device comprises an LED chip (2), a reflective cup (4) connected to the LED chip (2), and a light conversion material layer (3) located on the light emitting surface of the reflective cup (4); the LED chip (2) is electrically connected to a direct current power supply (9); a photodetector (5) is arranged on the second bracket (6-2), the photodetector (5) is electrically connected to an active meter (10), and the active meter (10) is electrically connected to an information processor (11); The microalgae solution container (1) is used to hold microalgae solutions of different densities and species; the LED chip (2) is used as an excitation light source for the light conversion material and to adjust the light brightness of the LED lighting device during testing; the light conversion material layer (3) is used to convert the short wavelength of the LED chip into a different long wavelength within the visible light range; the reflective cup (4) is used to collect the light generated by the LED chip and pass it through the light conversion material to excite the light conversion material layer (3) to emit light; the edge of the reflective cup (4) is used to fix the light conversion material layer (3); and the photodetector (5) is used to receive light emitted by the light source. The invention relates to a method for measuring the light signal of the microalgae solution container (1) by using a lifting platform (7) to adjust the vertical height at which the microalgae solution container (1) is placed during the test; the rotating turntable (8) is used to control the rotation angle of the microalgae solution container (1) and the LED lighting device relative to the photoelectric detector (5); the DC power supply (9) is used to adjust the parameters of the driving voltage and driving current of the LED chip (2); the source meter (10) is used to electrically connect the photoelectric detector (5) and to feed back the real-time photocurrent changes detected by the photoelectric detector (5); and the information processor (11) is used to obtain the information of the photocurrent obtained by the source meter (10) and to perform data analysis and calculation.

2. A microalgae density measurement system based on light detection according to claim 1, characterized in that: The LED chip (2) is any one of a short-wave light source such as a deep ultraviolet LED, an ultraviolet LED, or a blue light LED; the power of the LED chip (2) is selected according to the thickness of the microalgae solution container (1) to be tested; if the microalgae solution container (1) is thicker, a higher-power LED chip can be selected to emit light to ensure higher light penetration; if the microalgae solution container (1) is thinner, a lower-power LED chip can be selected to emit light to ensure that the test light power is within the test range.

3. A microalgae density measurement system based on light detection according to claim 1, characterized in that: The material of the light conversion material layer (3) is any one of the light conversion materials of fluorescent powder, quantum dots, perovskite and organic dye.

4. A microalgae density measurement system based on light detection according to claim 1, characterized in that: The reflective cup (4) is made of aluminum or acrylic.

5. A microalgae density measurement system based on light detection according to claim 1, characterized in that: The information processor (11) is an operating terminal device such as a computer or a tablet.

6. A method for measuring and correcting microalgae density based on light detection, implemented by a microalgae density measurement system based on light detection as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1, characterize the various luminous properties of the light conversion material and the LED chip, perform biological characterization on the microalgae solution, and use traditional testing methods to measure the parameters of the microalgae morphology, microalgae solution density, and microalgae color in the microalgae solution; Characterize the light response properties of the photodetector at different wavelengths; store all the parameters obtained from the test in the information processor for subsequent retrieval; Step 2, using a standard LED lighting device composed of a specific light conversion material and an LED chip to test the microalgae solution, obtain a real-time photocurrent, and perform analysis; Step 3, using a non-standard LED lighting device composed of any light conversion material and LED chip to test the microalgae solution, obtain a real-time photocurrent, and perform analysis; Step 4, using a calibration formula to calculate and correct the density of the microalgae solution tested under the non-standard LED lighting device conditions in step 3; Step 5, evaluating the calculated density of the microalgae solution to obtain the accuracy under different test conditions.

7. A method for measuring and correcting microalgae density based on light detection according to claim 6, characterized in that: Step 2 specifically includes: selecting a fixed light conversion material and LED chip, combining to produce an LED lighting device, and defining the LED lighting device as a standard LED lighting device; using the standard LED lighting device to test marine microalgae samples of different concentrations, and obtaining photocurrent through a photodetector; performing linear regression analysis on the photocurrent data obtained under the test conditions of marine microalgae of different densities, and fitting the data to obtain the change trend of the photocurrent under different marine microalgae densities; analyzing the relationship between the change of photocurrent and the density of marine microalgae, and obtaining the following formula: D M =α·P S (1); where D M is the density of marine microalgae, α is the proportionality coefficient, P S is the magnitude of the photocurrent; Among them, the test conditions include: general conditions and specific conditions; the general conditions include: the detection system can operate normally and remain stable to ensure that the microalgae solution with unknown microalgae density is evenly distributed; the incident angle of the light source is kept unchanged during the test; the specific conditions include: visible light of different wavelengths, different types of light sources, different algae species, different optical paths and any one of detecting microalgae density distribution.

8. A method for measuring and correcting microalgae density based on light detection according to claim 7, characterized in that: Step 3 specifically includes: Non-standard test phase: Since LED lighting devices based on light conversion materials have the characteristics of flexible regulation, the standard LED lighting device can be changed into a non-standard LED lighting device by changing the light conversion material and the LED chip, and the test of step 1 can be carried out.

9. A method for measuring and correcting microalgae density based on light detection according to claim 8, characterized in that: Step 4 specifically includes: the non-standard LED lighting device is characterized by adjustable light conversion materials and LED chips. Therefore, when the standard LED lighting device is changed to a non-standard LED lighting device, α and P in formula (1) are S The parameters of D will fluctuate, so it is necessary to recalibrate D through density correction. M With P S The calibration takes into account the photoconversion efficiency of different photoconversion materials, the effect of color change on the photosensitivity of the photodetector, and the absorption of different colors by microalgae; in this case, the calibrated photocurrent is defined as P C The ratio of the light conversion efficiency of the new light conversion material to the old light conversion material is LE, and the ratio of the sensitivity of the photodetector to the new light conversion material to the sensitivity of the photodetector to the old light conversion material is S R The light absorption rate of microalgae under the old light conversion material is A S The light absorption rate of microalgae under the old light conversion material is A C ; The above factors are used to calibrate the photocurrent P C To ensure that the calibrated photocurrent P C With the original photocurrent P S Consistent with D M Maintain clear relevance; Calibrated photocurrent P C This can be calculated using the following calibration formula: P C =P S ·THE R ·(1-A C ) / (1-A S ) (2); Formula (2) takes into account all changes to the microalgae solution and the photodetector in the process of replacing the non-standard standard LED lighting device; therefore, formula (2) is universal and can be applied not only to changes in different light conversion materials, but also to use under conditions of different LED chips; this adaptability is due to the fact that any changes that may be caused by changes in light conversion materials or LED chips have been taken into account in the calculation of LE; therefore, formula (2) ensures that the system can adapt to different configurations while maintaining the accuracy of density measurement; Calibrated microalgae density D MC It is described by the following formula (3), which includes the calibrated photocurrent P C , D MC =α·P C (3).

10. A method for measuring and correcting microalgae density based on light detection according to claim 9, characterized in that: Step 5 specifically includes: Accuracy calculation and analysis: In order to verify the accuracy of the LED lighting device after using the non-standard standard LED lighting device M The accuracy of the test is calculated using the following equation in the accuracy evaluation step 5. C ,

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