CN116223448A - Liquid refractive index measuring device and method based on shading effect - Google Patents
Liquid refractive index measuring device and method based on shading effect Download PDFInfo
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- CN116223448A CN116223448A CN202310197552.5A CN202310197552A CN116223448A CN 116223448 A CN116223448 A CN 116223448A CN 202310197552 A CN202310197552 A CN 202310197552A CN 116223448 A CN116223448 A CN 116223448A
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- 239000007788 liquid Substances 0.000 title claims abstract description 31
- 230000000694 effects Effects 0.000 title claims abstract description 21
- 238000000034 method Methods 0.000 title claims abstract description 18
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 23
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 23
- 239000010703 silicon Substances 0.000 claims abstract description 23
- 239000004065 semiconductor Substances 0.000 claims abstract description 22
- 238000006073 displacement reaction Methods 0.000 claims abstract description 13
- 230000003287 optical effect Effects 0.000 claims abstract description 10
- 239000011521 glass Substances 0.000 claims abstract description 7
- 239000003973 paint Substances 0.000 claims description 7
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 3
- 239000005329 float glass Substances 0.000 claims description 3
- 230000001678 irradiating effect Effects 0.000 claims description 2
- 239000007921 spray Substances 0.000 claims description 2
- 238000005259 measurement Methods 0.000 abstract description 16
- 238000004364 calculation method Methods 0.000 abstract description 5
- 238000009826 distribution Methods 0.000 abstract description 4
- 238000002474 experimental method Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 229920000742 Cotton Polymers 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007405 data analysis Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000011179 visual inspection Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
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Abstract
The invention discloses a liquid refractive index measuring device and method based on a shading effect, wherein the device part comprises an optical platform, a semiconductor laser, an aperture diaphragm, an objective table, a micro-displacement device and a universal meter. Based on the device, laser is emitted by the semiconductor laser and is emitted into the sample cell through the aperture diaphragm to form a shading pattern, the light intensity distribution of the shading pattern is collected through the silicon photocell, so that the diameter of a dark spot is obtained, and the refractive index of the sample is calculated by combining the thickness of glass of the sample cell. The refractive index of the liquid is obtained through calculation of the shading effect, the calculation result is high in accuracy and stability, and non-contact and real-time measurement can be achieved.
Description
Technical Field
The invention belongs to the technical field of liquid refractive index measurement, and particularly relates to a liquid refractive index measurement device and method based on a shading effect.
Background
Refractive index is one of the important parameters of the physical properties of a material. By measuring the refractive index of a material, we can indirectly derive other characteristic parameters of the substance, such as concentration, density, etc. In production and life, the refractive index measurement has important significance. At present, many methods for measuring the refractive index of liquid exist, but some of the methods have complicated measuring systems, are difficult to popularize in actual measurement, and the equipment of the methods is too expensive, so that the experimental cost is too high.
In optical experiments, refractive index is a fundamental and important optical parameter. Its appearance can be traced back to 1807, which was proposed and started to be used by Thomas Young. Since its advent, scientists have conducted many studies in which refractive index measurements are made, and some current measurement methods are designed and optimized for different needs to achieve more rapid and accurate measurements.
The current method for measuring the refractive index of liquid needs to sample the liquid to be measured, thus increasing the possibility of generating unnecessary errors and reducing the reliability of the experiment. In the preparation and production processes of chemical industry, medicine and the like, liquid is generally placed in a closed system. However, in order to monitor the production process, a method for acquiring physical and chemical parameters of the liquid in a non-contact manner is needed.
Disclosure of Invention
In order to solve the technical problems, the invention provides a liquid refractive index measuring device and method based on a shading effect, wherein the refractive index of the liquid is obtained by combining the device measurement based on the shading effect with a measuring method;
in order to achieve the technical effects, the invention is realized by the following technical scheme:
the utility model provides a liquid refractive index measuring device based on shading effect, includes optical platform, semiconductor laser, aperture diaphragm, objective table, little displacement device and universal meter, optical platform top is all arranged in to semiconductor laser, aperture diaphragm, objective table and little displacement device, aperture diaphragm sets up between semiconductor laser and objective table, hold the liquid that awaits measuring in the sample cell, place the sample cell on the objective table, fixedly connected with photoelectric sensor on the little displacement device, photoelectric sensor's input is equipped with hides the unthreaded hole, and its photosurface is facing to the back lateral wall of sample cell, be connected through the wire between universal meter and the photoelectric sensor.
Preferably, the laser beam emitted by the semiconductor laser is a green beam with the power of 5mW and the wavelength of 532 nm;
preferably, the aperture size of the aperture diaphragm is 0.8mm; the aperture size of the shading hole is 1-1.5mm;
preferably, the photosensor is a silicon photocell.
A method for measuring refractive index of a liquid based on a shading effect, comprising the steps of:
s1: opening the semiconductor laser, and adjusting the semiconductor laser to enable the laser beam to be parallel to the horizontal plane;
s2: adjusting the position of the lens barrel of the reading microscope to enable the lens barrel to be positioned at a half stroke of the graduated scale;
s3: the height of the lens barrel of the reading microscope is adjusted, so that laser beams can be just injected from a shading hole in front of the silicon photocell;
s4: adjusting the angle of the light beam to enable the light beam to be perpendicular to the photosensitive surface of the silicon photocell;
s5: adding an aperture diaphragm with an aperture of 1.5mm in front of the semiconductor laser;
s6: placing the sample cell between the aperture diaphragm and the reading microscope lens barrel, wherein the paint surface is arranged on one side of the silicon photocell, the light surface is arranged on one side of the laser, the paint surface is as close to the silicon photocell as possible, but does not contact with the silicon photocell, and simultaneously, adjusting the angle of the sample cell to be perpendicular to the laser beam;
s7: rotating the reading microscope drum clockwise to adjust the lens barrel to the left of the dark spot;
s8: covering the light path by a light shield to prevent stray light from irradiating the photosensitive surface of the silicon photocell;
s9: rotating the drum anticlockwise, starting to stop reading in the first circle, starting to record the output voltage value of the silicon photocell every five grids around the edge of the dark spot every time in the second circle, recording data every 20 grids every time in the dark spot, and always moving the lens barrel to the right of the dark spot;
s10: finding out two maximum values at the edge of the circular dark spot from the output voltage value of the silicon photocell, wherein the positions corresponding to the maximum values are two points on the diameter of the circular dark spot, and the distance d between the two points is the diameter of the dark spot;
s11: measuring the thickness h of the glass of the sample cell;
s12: calculating the refractive index of the sample by a formula
Wherein h is the thickness of the wall of the container, and d is the diameter of the dark spot;
s13: according to the measured refractive index n 1 And calculating to obtain the alcohol concentration.
Preferably, in the step S5, the aperture center of the aperture diaphragm is required to coincide with the beam cross section, so as to ensure that the light intensity distribution of the obtained circular dark spot at the position symmetrical about the light spot center is consistent;
preferably, the sample cell in the step S6 can be made of float glass or quartz glass, and one side of the outer side of the sample cell is sprayed with white self-spray paint;
preferably, in S9, five cells are each rotated near the edge of the dark spot from the second turn, i.e. the lens barrel is moved to the right by 0.05mm.
The beneficial effects of the invention are as follows:
by utilizing the method provided by the invention, the refractive index of the liquid is obtained based on the calculation of the shading effect, and the calculation result has high precision and good stability. Importantly, the refractive index measurement can be realized by using the measurement method provided by the invention.
Drawings
FIG. 1 is a diagram of a measurement device;
FIG. 2 is a dark spot diagram I;
FIG. 3 is a dark spot diagram II;
fig. 4 is a graph of the intensity distribution of a circular dark spot.
In the drawings, the structures represented by the reference numerals are as follows:
the device comprises a 1-optical platform, a 2-semiconductor laser, a 3-aperture diaphragm, a 4-sample cell, a 5-objective table, a 6-shading hole, a 7-photoelectric sensor, an 8-micro displacement device, a 9-universal meter, a 10-wire and 11-liquid to be measured.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
The utility model provides a liquid refractive index measuring device based on shading effect, includes optical platform 1, semiconductor laser 2, aperture diaphragm 3, objective table 5, little displacement device 8 and universal meter 9, optical platform 1 top is all arranged in to semiconductor laser 2, aperture diaphragm 3, objective table 5 and little displacement device 8, aperture diaphragm 3 sets up between semiconductor laser 2 and objective table 5, be equipped with the liquid that awaits measuring in the sample cell 4, be equipped with sample cell 4 on the objective table 5, fixedly connected with photoelectric sensor 7 on little displacement device 8, photoelectric sensor 7's input is equipped with hides the light hole 6, and its photosurface is facing to the rear sidewall of sample cell 4, be connected through the wire between universal meter 9 and the photoelectric sensor 7.
The laser beam emitted by the semiconductor laser 2 is a green light beam with the power of 5mW and the wavelength of 532 nm;
the aperture size of the aperture diaphragm 3 is 0.8mm; the aperture size of the shading hole 6 is 1-1.5mm;
the photosensor 7 is a silicon photocell.
Example 2
Before operation, the sample cell, the laser and the silicon photocell are wiped by dipping the cotton swab with alcohol. Setting up and completing the debugging of the optical path, we can start the measurement of the refractive index of the liquid. Pouring liquid to be measured into the sample cell, opening the laser, and adjusting the base of the sample cell to enable the round dark spot to be located at the center of the sample cell, so that data acquisition in the future is facilitated. The semiconductor laser selects green light laser with 5mw of power and 532nm of wavelength, so that laser beams are emitted into the shading hole and vertically irradiate on the photosensitive surface of the silicon photocell. A circular dark spot pattern, i.e. "shading effect", as shown in fig. 2, 3, was observed to form on the paint surface of the sample cell. The pattern center is a bright spot with extremely strong light intensity, the outside of the bright spot is a circle of dark ring, the periphery of the dark ring is a bright field, the light intensity of the peripheral bright field is weaker than that of the central bright spot, and the boundaries of the three bright and dark areas are quite clear. The reading microscope is used as a micro displacement platform to drive the silicon photocell to stably move in the shading pattern area, so that jump of voltage reading on the digital multimeter can be seen.
1. Data acquisition
The aim of the acquisition is to extract the diameter of the circular dark spot. We start the measurement from one side of the diameter of the circular dark spot, because it is the remote sensing of the manual control reading microscope, we move the initial measurement point out of the way to prevent missing data. Firstly, recording a group of data every 0.2mm, when the round dark spot is detected by visual inspection, recording a group of data every 0.05mm, and when the round dark spot is detected, recording a group of data every 0.2 mm; the other end of the diameter of the circular dark spot is also measured by the same method, so that the time for experiment is greatly reduced.
Observing the shading effect pattern, and performing debugging and repeated measurement for a plurality of times, wherein eight groups of data are successfully measured for the diameter of the circular dark spot, and each group of data is about 200.
2. Data processing
In order to study the measurement accuracy of the experimental method for measuring the refractive index of the liquid by utilizing the shading effect principle, a self-made quartz glass and an acrylic plate are selected as a sample cell. Alcohol is used as a liquid to be measured, and data are measured and analyzed;
the result of data analysis of the light intensity distribution of the circular dark spots measured by us through origin software is shown in fig. 4;
according to the principle, the inflection point is a round dark spot boundary. From the experimental data, the positions at the inflection points on both sides were 43.000mm and 12.350mm, respectively. The effective diameter of the circular dark spot is 30.650mm.
Since the measured diameter d is a single measurement, the total uncertainty is expressed in terms of class B uncertainty.
Reading microscope displacement uncertainty:
U d ＝U dB ＝Δ instrument 1 ＝0.005(mm)
Glass thickness was measured with a screw micrometer:
glass thickness: uncertainty degree
The glass thickness was measured using a screw micrometer, with class B uncertainty taking half the minimum index value:
U hB ＝Δ instrument 2 ＝0.005(mm)
Relative uncertainty:
glass thickness
The refractive index calculation formula is:
this can be achieved by:
float glass refractive index (known): 1.516
Substituting the formula to calculate:
the calculated refractive index is:
n= 1.3613 ±0.001 the concentration of alcohol was calculated based on the obtained alcohol refractive index 1.3613.
Claims (8)
1. The utility model provides a liquid refractive index measuring device based on shading effect, its characterized in that includes optical platform, semiconductor laser, aperture diaphragm, objective table, little displacement device and universal meter, optical platform top is all arranged in to semiconductor laser, aperture diaphragm, objective table and little displacement device, aperture diaphragm sets up between semiconductor laser and objective table, be equipped with the liquid that awaits measuring in the sample cell, be equipped with the sample cell on the objective table, fixedly connected with photoelectric sensor on the little displacement device, photoelectric sensor's input is equipped with hides the light hole, and its photosurface is just opposite the back lateral wall of sample cell, be connected through the wire between universal meter and the photoelectric sensor.
2. The device for measuring the refractive index of liquid based on the shading effect according to claim 1, wherein the laser beam emitted by the semiconductor laser is a green beam with power of 5mW and wavelength of 532 nm.
3. The device for measuring refractive index of liquid based on shading effect according to claim 1, wherein the aperture size of the aperture stop is 0.8mm; the aperture size of the shading hole is 1-1.5mm.
4. The device of claim 1, wherein the photosensor is a silicon photocell.
5. The liquid refractive index measuring method based on the shading effect is characterized by comprising the following steps of:
s1: opening the semiconductor laser, and adjusting the semiconductor laser to enable the laser beam to be parallel to the horizontal plane;
s2: adjusting the position of the lens barrel of the reading microscope to enable the lens barrel to be positioned at a half stroke of the graduated scale;
s3: the height of the lens barrel of the reading microscope is adjusted, so that laser beams can be just injected from a shading hole in front of the silicon photocell;
s4: adjusting the angle of the light beam to enable the light beam to be perpendicular to the photosensitive surface of the silicon photocell;
s5: adding an aperture diaphragm with an aperture of 1.5mm in front of the semiconductor laser;
s6: placing the sample cell between the aperture diaphragm and the reading microscope lens barrel, wherein the paint surface is arranged on one side of the silicon photocell, the light surface is arranged on one side of the laser, the paint surface is as close to the silicon photocell as possible, but does not contact with the silicon photocell, and simultaneously, adjusting the angle of the sample cell to be perpendicular to the laser beam;
s7: rotating the reading microscope drum clockwise to adjust the lens barrel to the left of the dark spot;
s8: covering the light path by a light shield to prevent stray light from irradiating the photosensitive surface of the silicon photocell;
s9: rotating the drum anticlockwise, starting to stop reading in the first circle, starting to record the output voltage value of the silicon photocell every five grids around the edge of the dark spot every time in the second circle, recording data every 20 grids every time in the dark spot, and always moving the lens barrel to the right of the dark spot;
s10: finding out two maximum values at the edge of the circular dark spot from the output voltage value of the silicon photocell, wherein the positions corresponding to the maximum values are two points on the diameter of the circular dark spot, and the distance d between the two points is the diameter of the dark spot;
s11: measuring the thickness h of the glass of the sample cell;
s12: calculating the refractive index of the sample by a formula
Wherein h is the thickness of the wall of the container, and d is the diameter of the dark spot;
s13: according to the measured refractive index n 1 And calculating to obtain the alcohol concentration.
6. The method for measuring refractive index of liquid based on shading effect according to claim 5, wherein the center of the aperture stop in S5 is required to coincide with the cross section of the light beam.
7. The method for measuring refractive index of liquid based on shading effect according to claim 5, wherein the sample cell in the step S6 can be made of float glass or quartz glass, and white self-spray paint is sprayed on one surface of the outer side of the sample cell.
8. The method of claim 5, wherein the lens barrel is moved to the right by 0.05mm every five cells around the edge of the dark spot from the second turn in S9.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117761010A (en) * | 2024-02-22 | 2024-03-26 | 山西大学 | high-precision laser liquid refractive index measuring device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117761010A (en) * | 2024-02-22 | 2024-03-26 | 山西大学 | high-precision laser liquid refractive index measuring device |
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