Transparent solution concentration measuring system based on linear array CCD (Charge Coupled Device)
By designing a transparent solution concentration measurement system based on linear array CCD, using laser refractive method and linear array CCD to capture the spot position, the existing solution concentration measurement methods are solved, and the problem of low resolution and difficult operation is achieved, and a fast, accurate and easy-to-operate solution concentration measurement is achieved.
Patent Information
- Application Number
- CN202421113906.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-21
- Publication Date
- 2025-04-25
- Estimated Expiration
- 2034-05-21
AI Technical Summary
The existing solution concentration measurement methods have problems such as low resolution, large physical scale, difficult to operate, relying on visual, subjective data measurement, inconvenient use in flow systems, and expensive equipment.
A transparent solution concentration measurement system based on linear array CCD is designed, including a laser, a diaphragm, a beam expander, a polarizer, a triangular glassware and a linear array CCD. The solution concentration is measured by laser refractive method, and the linear array CCD is used to capture the spot position to achieve fast and accurate solution concentration measurement.
It realizes rapid and accurate measurement of solution concentration, with simple principles, obvious experimental phenomena, easy to operate, high operability, and is not affected by environmental factors and high sensitivity.
Smart Images
Figure CN222800605U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the fields of optical engineering and analytical chemistry, in particular to a transparent solution concentration measurement system based on a linear array CCD. Background Art
[0002] Solution concentration refers to the amount of solute contained in a unit solution. In many fields such as basic research, chemical industry, medical diagnosis, food manufacturing, environmental protection, etc., the concentration of the solution needs to be accurately measured and controlled.
[0003] Traditional methods for measuring solution concentration mainly include specific gravity method, sonic wave method and spectroscopy method. The specific gravity method uses a liquid specific gravity balance to measure the specific gravity of the liquid to be tested, and determines the corresponding solution concentration based on the specific gravity of the liquid, but its operation steps are relatively cumbersome; the sonic wave method uses the reflection wave characteristics, amplitude characteristics, phase difference characteristics, and spectrum characteristics of sound waves to indirectly measure the solution concentration, but the measurement results are easily affected by environmental factors; the spectroscopy method mainly uses the refraction, interference, and diffraction characteristics of light to indirectly measure the solution concentration, which requires precise and expensive experimental facilities, and can only be used for the measurement of non-flowing liquids. Due to the different measurement methods, it has strong limitations. For example, the Abbe refractometer is a contact measurement, and the polarimeter is used to measure concentration. It is only applicable to optically active solutions, and it depends on the human eye to judge whether the brightness of the three-dimensional field of view is the same. Because of the influence of personal subjective factors, it is easy to produce obvious differences in measurement results. These mature instruments have low resolution, large physical scale, difficult to operate, rely on visualization, subjective data measurement, inconvenient for use in flow systems, and expensive equipment. Therefore, it is very necessary to design a transparent solution concentration measurement system with a simple structure, accurate measurement, easy operation, and the ability to collect data in real time through sensors.
[0004] With the advancement of modern optical and optoelectronic technologies, the precision manufacturing technology and performance of charge-coupled devices (CCDs) have developed rapidly, making it possible to measure the refractive index change of liquids using the high resolution of CCDs and providing a new means for measuring liquid concentration.
[0005] At present, the liquid concentration measurement methods based on CCD mainly include the optical refraction method based on the linear CCD and the prism minimum deviation angle method based on the linear CCD. The optical refraction method based on the linear CCD is to let a beam of parallel light obliquely incident on one side of the rectangular glass containing the solution to be measured, and emit from the other side, which is received by the CCD. The outgoing light is parallel to the incident light but not on the same straight line, that is, the outgoing light has a lateral displacement relative to the incident light. Since the refractive index of the solution is affected by the concentration change, this lateral displacement changes with the change of liquid concentration, so the liquid level can be measured according to the displacement. This method uses LED as the light source. The glass and liquid cannot be too thick, otherwise the light signal will be weakened, and the sensitivity is not high. The change of the incident angle will increase the measurement error. The prism minimum deviation angle method based on the linear CCD is to put the solution into a hollow prism, a laser beam is incident on the prism, and the light emitted from the other side has a deviation angle relative to the incident light. The position of the image formed on the CCD when the outgoing light meets the minimum deviation angle is recorded. When the concentration of the solution changes, the refractive index of the liquid changes, which causes the minimum deflection angle to change, and the imaging on the CCD shifts. By measuring the relationship between the minimum deflection angle and the concentration, the liquid concentration can be measured by a table lookup method. This method approximates the relationship between the minimum deflection angle and the concentration as a linear fit, and the error is large when measuring the deflection angle, which is easily affected by the external environment and has low sensitivity. Utility Model Content
[0006] The utility model aims to provide a transparent solution concentration measurement system based on a linear array CCD which has a simple structure, accurate measurement, is easy to operate, and can collect data in real time through a sensor.
[0007] The technical solution to achieve the purpose of the utility model is: a transparent solution concentration measurement system based on a linear array CCD, comprising a laser, an aperture, a beam expander, a polarizer, a triangular prism glass vessel and a linear array CCD arranged in sequence along the optical path and on the same optical axis;
[0008] The bottom surface of the triangular prism-shaped glass vessel is an isosceles right triangle, and the two sides of the isosceles right triangle correspond to the first side surface and the second side surface of the triangular prism, respectively, and the solution to be tested is contained inside;
[0009] The laser is fixed on the bracket, and the laser emitted by the laser is vertically incident on the first side of the triangular prism-shaped glass container and emitted from the second side of the triangular prism-shaped glass container;
[0010] The aperture is used for beam shaping. By controlling the amount of light beam passing through the aperture, the intensity of the light beam can be adjusted to produce light of a set shape or distribution to meet measurement requirements.
[0011] The beam expander and polarizer are used to adjust the divergence and intensity of the light beam so that the light can be evenly irradiated onto the surface of the solution to be tested;
[0012] The linear array CCD is installed behind the triangular prism glass vessel to capture the position of the light spot after the laser is refracted through the solution to be tested, so that a clear light spot is formed on the linear array CCD.
[0013] Furthermore, the laser adopts an integrated helium-neon laser with a power of 50mW, emitting parallel monochromatic collimated laser with a wavelength of 980nm.
[0014] Furthermore, the diaphragm is an adjustable diaphragm with a light-transmitting aperture of 20 mm, an outer diameter of 30 mm, a thickness of 5.5 mm, and a blade made of stainless steel.
[0015] Furthermore, the beam expander adopts a 10X aspheric beam expander, the input beam diameter is 1mm, and the divergence angle is 0.5mrad. After using the beam expander, the output beam diameter will become 10mm, and the divergence angle will increase to 5mrad.
[0016] Furthermore, the polarization direction of the polarizer is vertical, the size is 25.4 mm×25.4 mm, the transmittance is 95%, and the working wavelength range covers the entire visible light, that is, 400 nm to 700 nm.
[0017] Furthermore, the triangular prism-shaped glass vessel has a height of 150 mm, an isosceles right triangle at the bottom with a waist length of 30 mm, a glass wall thickness of 2 mm, and is made of borosilicate glass.
[0018] Furthermore, the number of pixels of the linear array CCD is 4096 pixels, the pixel pitch is 7.4 μm, the spectral response covers the visible light range of 400 nm to 700 nm, and the quantum efficiency is greater than 50% at 500 nm.
[0019] Compared with the prior art, the present invention has the following significant advantages: (1) it realizes rapid and accurate measurement of solution concentration and has broad application prospects; (2) it has a simple principle, obvious experimental phenomena, is easy to operate, and has high operability. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 The utility model is a schematic diagram of the optical path structure of a transparent solution concentration measurement system based on a linear array CCD.
[0021] Figure 2 It is a structural schematic diagram of a transparent solution concentration measurement system based on a linear array CCD constructed in an embodiment of the utility model.
[0022] Figure 3 It is a calibration diagram of the NaCl solution concentration-peak position relationship in the embodiment of the utility model.
[0023] Figure 4It is a schematic diagram of the results of measuring the concentration of the alcohol solution in the embodiment of the utility model. DETAILED DESCRIPTION
[0024] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.
[0025] The utility model discloses a transparent solution concentration measurement system based on a linear array CCD. Figure 1 As shown, it includes a laser 1, an aperture 2, a beam expander 3, a polarizer 4, a triangular prism glass vessel 5 and a linear array CCD 6 which are sequentially arranged along the optical path and share the same optical axis;
[0026] The bottom surface of the triangular prism-shaped glass vessel 5 is an isosceles right triangle, and the two legs of the isosceles right triangle correspond to the first side surface and the second side surface of the triangular prism, respectively, and the solution to be tested is contained inside;
[0027] The laser 1 is fixed on the bracket, and the laser emitted by the laser 1 is vertically incident on the first side of the triangular prism-shaped glass container 5, and is emitted from the second side of the triangular prism-shaped glass container 5;
[0028] Aperture 2 is used for beam shaping. By controlling the amount of light beam passing through aperture 2, the intensity of the light beam is adjusted to generate light of a set shape or distribution to meet the measurement requirements.
[0029] The beam expander 3 and the polarizer 4 are used to adjust the divergence and intensity of the light beam so that the light is evenly irradiated onto the surface of the solution to be tested;
[0030] The linear array CCD6 is installed behind the triangular prism-shaped glass vessel 5 to capture the position of the light spot after the laser is refracted by the solution to be tested, so that a clear light spot is formed on the linear array CCD6.
[0031] As a specific example, the laser 1 is an integrated helium-neon laser 1 with a power of 50 mW, emitting parallel monochromatic collimated laser with a wavelength of 980 nm.
[0032] As a specific example, the diaphragm 2 is an adjustable diaphragm 2 with a light-transmitting aperture of 20 mm, an outer diameter of 30 mm, a thickness of 5.5 mm, and blades made of stainless steel.
[0033] As a specific example, the beam expander 3 uses a 10X aspheric beam expander 3, the input beam diameter is 1 mm, and the divergence angle is 0.5 mrad. After using the beam expander 3, the output beam diameter will become 10 mm, and the divergence angle will increase to 5 mrad.
[0034] As a specific example, the polarization direction of the polarizer 4 is vertical, the size is 25.4 mm×25.4 mm, the transmittance is 95%, and the working wavelength range covers the entire visible light, that is, 400 nm to 700 nm.
[0035] As a specific example, the triangular prism-shaped glass vessel 5 has a height of 150 mm, an isosceles right triangle at the bottom with a waist length of 30 mm, a glass wall thickness of 2 mm, and is made of borosilicate glass.
[0036] As a specific example, the number of pixels of the linear array CCD6 is 4096 pixels, the pixel pitch is 7.4 μm, the spectral response covers the visible light range of 400 nm to 700 nm, and the quantum efficiency is greater than 50% at 500 nm.
[0037] The utility model discloses a measuring method of a transparent solution concentration measuring system based on a linear array CCD, comprising the following steps:
[0038] Step 1: Build a transparent solution concentration measurement system based on linear array CCD;
[0039] Step 2: Adjust and calibrate the optical path;
[0040] Step 3, measuring the standard solution spot data and establishing a standard solution database;
[0041] Step 4, measuring the concentration of the solution to be tested;
[0042] Step 5: Analyze the measurement results and verify their accuracy.
[0043] Furthermore, the construction of a transparent solution concentration measurement system based on a linear array CCD as described in step 1 is as follows: Figure 2 As shown, the details are as follows:
[0044] Step 1.1, fix the laser on the bracket and adjust its angle to ensure that the laser can vertically enter the triangular prism glassware;
[0045] Step 1.2, place a triangular prism-shaped glass container in the laser path so that the solution to be tested can be contained inside;
[0046] Step 1.3, install a beam expander and a polarizer between the laser and the triangular prism glass vessel, adjust the divergence and intensity of the beam, and ensure that the light is evenly irradiated to the surface of the solution;
[0047] Step 1.4: Install the linear array CCD camera at an appropriate position behind the triangular prism glass vessel after the laser is refracted, so as to capture the position of the light spot after refraction through the solution.
[0048] Furthermore, the optical path adjustment and calibration described in step 2 are specifically as follows:
[0049] Step 2.1, when there is no solution in the triangular prism glass container, adjust the position of the linear array CCD so that the laser emitted by the laser forms a clear light spot on the linear array CCD;
[0050] Step 2.2: Add distilled water to the triangular prism glass container and adjust the system again to ensure that the outgoing light is incident vertically on the CCD receiver.
[0051] Furthermore, the standard solution spot data is measured in step 3 to establish a standard solution database, as follows:
[0052] Step 3.1, use standard solutions of different concentrations to measure data and collect spot position data of solutions of different concentrations;
[0053] Step 3.2: Process the collected spot position data of solutions of different concentrations and establish a standard solution database.
[0054] Furthermore, the data measurement is performed using standard solutions of different concentrations as described in step 3.1, and the spot position data of solutions of different concentrations are collected, as follows:
[0055] Prepare a series of standard solutions of different concentrations to establish the corresponding relationship between concentration and spot position. Pour these standard solutions into triangular prism-shaped glass vessels respectively, and record the peak position data value of the spot on the linear array CCD at each concentration; repeat the measurement to improve the accuracy and repeatability of the data.
[0056] Furthermore, the spot position data of the solutions with different concentrations collected in step 3.2 are processed to establish a standard solution database, as follows:
[0057] The collected peak position data were fitted with polynomials using MATLAB data processing software to establish a mathematical model of the calibration curve between solution concentration and peak position.
[0058] Furthermore, the concentration of the solution to be tested described in step 4 is measured as follows:
[0059] Step 4.1, pour the solution to be tested into a triangular prism-shaped glass container, and measure the spot peak position value of the solution to be tested;
[0060] Step 4.2: Substitute the measured spot peak position value of the solution to be tested into the established calibration curve mathematical model to obtain the concentration of the solution to be tested.
[0061] Furthermore, the analysis of the measurement results described in step 5 verifies the accuracy of the measurement results, as follows:
[0062] Step 5.1, compare the measured concentration value with the known concentration of the standard solution, calculate the relative error, and verify the accuracy of the measurement method;
[0063] Step 5.2: If the relative error exceeds the set threshold, analyze the source of the error and adjust the experimental parameters or system configuration as needed.
[0064] Example 1
[0065] In this embodiment, the concentration of NaCl solution is measured. First, NaCl solution is added to the container, and the intensity of the incident light is adjusted so that the CCD receives the signal emitted by the laser. Then, the peak position of the standard solution is measured, and the peak positions of the prepared standard solutions are measured in turn. The corresponding concentrations and CCD light intensity distributions are recorded and plotted in a chart form. Then, polynomial fitting is performed on the peak position and concentration data using MATLAB data processing software to obtain a calibration curve of the concentration-peak position relationship of the NaCl solution, as shown in FIG. Figure 3 As shown; finally, pour the NaCl solution to be tested into the container for measurement, and substitute the measured peak value into the calibration curve to obtain the concentration of the liquid to be tested.
[0066] Example 2
[0067] This embodiment measures the concentration of an alcohol solution. First, add an alcohol solution into a container, and adjust the intensity of the incident light so that the CCD receives the signal emitted by the laser; then measure the peak position of the standard solution, measure the peak position of the prepared standard solution in turn, and record the corresponding concentration and CCD light intensity distribution, and draw them into a graph; then use MATLAB data processing software to perform polynomial fitting on the peak position and concentration data to obtain a calibration curve of the concentration-peak position relationship of the alcohol solution; finally, pour the alcohol solution to be tested into the container for measurement, and bring the measured peak value into the calibration curve to obtain the concentration of the liquid to be tested. The measured alcohol solution concentration result is as follows: Figure 4 shown.
[0068] It can be seen that the transparent solution concentration measurement method based on linear array CCD provided by the utility model realizes rapid and accurate measurement of solution concentration, and has simple principle, obvious experimental phenomenon, easy operation and high operability.
[0069] The above are only preferred implementations of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.
Claims
1. A transparent solution concentration measurement system based on linear array CCD, characterized in that: It comprises a laser (1), an aperture (2), a beam expander (3), a polarizing plate (4), a triangular prism glass vessel (5) and a linear array CCD (6) which are sequentially arranged along an optical path and share an optical axis; The bottom surface of the triangular prism-shaped glass container (5) is an isosceles right triangle, the two legs of the isosceles right triangle correspond to the first side surface and the second side surface of the triangular prism respectively, and the solution to be tested is contained inside; The laser (1) is fixed on a bracket, and laser light emitted by the laser (1) is vertically incident on a first side of the triangular prism-shaped glass vessel (5) and emitted from a second side of the triangular prism-shaped glass vessel (5); The aperture (2) is used for beam shaping. The intensity of the beam is adjusted by controlling the amount of the beam passing through the aperture (2) to generate light of a set shape or distribution to meet measurement requirements. The beam expander (3) and the polarizer (4) are used to adjust the divergence and light intensity of the light beam so that the light is evenly irradiated onto the surface of the solution to be tested; The linear array CCD (6) is installed behind the triangular prism-shaped glass vessel (5) to capture the position of the light spot after the laser is refracted by the solution to be tested, so that a clear light spot is formed on the linear array CCD (6).
2. The transparent solution concentration measurement system based on linear array CCD (6) according to claim 1, characterized in that: The laser (1) adopts an integrated helium-neon laser (1) with a power of 50 mW and emits parallel monochromatic collimated laser light with a wavelength of 980 nm.
3. The transparent solution concentration measurement system based on linear array CCD (6) according to claim 1, characterized in that: The diaphragm (2) is an adjustable diaphragm (2) with a light transmission aperture of 20 mm, an outer diameter of 30 mm, a thickness of 5.5 mm, and blades made of stainless steel.
4. The transparent solution concentration measurement system based on linear array CCD (6) according to claim 1, characterized in that: The beam expander (3) adopts a 10X aspheric beam expander (3), the input beam diameter is 1 mm, and the divergence angle is 0.5 mrad. After using the beam expander (3), the output beam diameter will become 10 mm, and the divergence angle will increase to 5 mrad.
5. The transparent solution concentration measurement system based on linear array CCD (6) according to claim 1, characterized in that: The polarization direction of the polarizer (4) is vertical, the size is 25.4 mm×25.4 mm, the light transmittance is 95%, and the working wavelength range covers the entire visible light, that is, 400 nm to 700 nm.
6. The transparent solution concentration measurement system based on linear array CCD (6) according to claim 1, characterized in that: The triangular prism-shaped glass vessel (5) has a height of 150 mm, an isosceles right triangle at the bottom with a waist length of 30 mm, a glass wall thickness of 2 mm, and is made of borosilicate glass.
7. The transparent solution concentration measurement system based on linear array CCD (6) according to claim 1, characterized in that: The number of pixels of the linear array CCD (6) is 4096 pixels, the pixel pitch is 7.4 μm, the spectral response covers the visible light range of 400 nm to 700 nm, and the quantum efficiency is greater than 50% at 500 nm.