CN116465860B - Transparent liquid concentration measuring device based on double wedge and Mach-Zehnder interferometer - Google Patents
Transparent liquid concentration measuring device based on double wedge and Mach-Zehnder interferometer Download PDFInfo
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- 239000007788 liquid Substances 0.000 title claims abstract description 65
- 238000005192 partition Methods 0.000 claims abstract description 36
- 230000003287 optical effect Effects 0.000 claims description 29
- 238000000034 method Methods 0.000 claims description 27
- 238000005259 measurement Methods 0.000 claims description 22
- 230000001681 protective effect Effects 0.000 claims description 9
- CPBQJMYROZQQJC-UHFFFAOYSA-N helium neon Chemical compound [He].[Ne] CPBQJMYROZQQJC-UHFFFAOYSA-N 0.000 claims description 3
- 239000005304 optical glass Substances 0.000 claims description 3
- 239000012780 transparent material Substances 0.000 claims description 3
- 230000007547 defect Effects 0.000 abstract description 2
- 230000007812 deficiency Effects 0.000 abstract description 2
- 210000004027 cell Anatomy 0.000 description 31
- 239000000243 solution Substances 0.000 description 20
- 239000011521 glass Substances 0.000 description 14
- 239000012086 standard solution Substances 0.000 description 12
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 8
- 238000010586 diagram Methods 0.000 description 6
- 239000011780 sodium chloride Substances 0.000 description 4
- CZMRCDWAGMRECN-UGDNZRGBSA-N Sucrose Chemical compound O[C@H]1[C@H](O)[C@@H](CO)O[C@@]1(CO)O[C@@H]1[C@H](O)[C@@H](O)[C@H](O)[C@@H](CO)O1 CZMRCDWAGMRECN-UGDNZRGBSA-N 0.000 description 3
- 229930006000 Sucrose Natural products 0.000 description 3
- 239000011295 pitch Substances 0.000 description 3
- 239000005720 sucrose Substances 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 238000003384 imaging method Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 210000000540 fraction c Anatomy 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000002608 ionic liquid Substances 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
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- 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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Abstract
A transparent liquid concentration measuring device based on a double wedge interferometer and a Mach-Zehnder interferometer relates to a transparent liquid concentration measuring device. The invention aims to solve the problems that the existing Abbe refractometer and Mach-Zehnder interferometer have defects and deficiencies when the liquid refractive index is measured. The sample cell is a double-wedge sample cell, the sample cell consists of a rectangular groove body, a central partition board and a partition wall, the central partition board is arranged in the rectangular groove body along the diagonal line of the rectangular groove body, the central partition board divides the rectangular groove body into two right-angle triangular groove bodies, one right-angle triangular groove body is a standard liquid B area, the partition wall is arranged in the other right-angle triangular groove body, and the partition wall divides the other right-angle triangular groove body into a standard liquid A area and a solution area to be measured. The invention belongs to the field of physical teaching.
Description
Technical Field
The invention relates to a transparent liquid concentration measuring device, and belongs to the field of physical teaching.
Background
The current methods for measuring the concentration of the liquid include a gravity method, a conductivity method, an ultrasonic method, an optical method and the like, and are applicable to a transparent liquid optical method. Compared with other methods, the optical method has the advantages of high precision, no need of contact, no pollution to liquid and the like.
The refractive index is the most obvious and common optical property of the transparent liquid medium, and is closely related to the concentration of the liquid, and the concentration of the transparent liquid can be calculated by selecting the refractive index as the measured physical quantity.
The refractive index of a liquid for light of a certain wavelength is affected by concentration and temperature; taking NaCl solution as an example, for light with a wavelength of 589.3nm, the refractive index n, the mass fraction c% and the temperature TK have the following empirical formula:
n＝1.3373+(1.7682·10 -3 )c-(5.8·10 -6 )c 2 -(1.3531·10 -4 )(T-273.15)-(5.1·10 -8 )(T-273.15) 2 (1)，
the second order term for the concentration amount can be omitted in general, so that the refractive index and the concentration can be approximately considered to satisfy the linear relationship at a constant temperature, and the correlation coefficient reaches 0.99963. From equation (1), if the ambient temperature changes, the linear relationship between refractive index and concentration remains true, and the slope of the linear relationship is not affected by temperature. Most ionic liquids conform to this linear relationship and therefore the concentration of the solution can be calculated by measuring the refractive index.
Methods for measuring refractive index can be broadly classified into two types, geometrical optics and wave optics.
The geometrical optics method mainly comprises critical angle method, imaging method, spectroscope method, abbe refractometer method, etc. The measuring principle is that the refractive index of the object to be measured is obtained by measuring the relevant angles according to the law of refraction and the law of reflection.
Among the wave optics methods, wedge interference, michelson interference, fabry-perot (F-P) interference, rayleigh interferometer, brewster angle, polarimeter and the like are more commonly used methods, and the optical characteristics of the medium are measured according to the phenomena of optical path, polarization, absorption and the like of light in the medium.
For refractive index measurement, abbe refractometer is the most widely used at present, the principle is as shown in fig. 3, a microscope is used for measuring critical refraction angle of liquid-glass interface, the ratio of the refractive index of liquid to the refractive index of glass is measured through a refraction law, and the refractive index measurement accuracy is high and can reach 0.0002. However, the Abbe refractometer has the following problems in measuring the refractive index:
1. in the case where the Abbe refractometer uses ambient white light as a light source, a chromatic dispersion phenomenon occurs, and it is difficult to determine a semi-cloudy line. Adding a compensation prism can solve this problem, but makes the device more complex;
2. limited by the critical refraction angle of the glass refractive index, the measurement range of the refractive index is limited to between 1.3 and 1.7.
Meanwhile, the existing Abbe refractometer on the market performs calibration on the brix of the mass fraction of the sucrose solution, and can directly read the concentration of the sucrose solution, but has the following problems:
1. because the refractive index of the liquid is not only related to the concentration, but also influenced by the temperature, an external thermostat is needed to control the temperature, and the concentration can be accurately measured;
2. most of the existing Abbe refractometers only realize the calibration between the concentration and refraction angle of the sucrose solution, and the refractive index is required to be measured when other solutions are measured, and then the concentration is indirectly calculated;
the method for measuring the refractive index by using the Mach-Zehnder interferometer and the rotary cuvette method is proposed by the He Maogang team of the Western-style traffic university, has the advantages of high precision and sensitivity, can eliminate the window wiping interference of the cuvette through an algorithm, and the like, and has the refractive index precision reaching one thousandth, but also has the following problems:
1. the angle measurement is a main source of uncertainty, so that the stability and the precision of the electric control turntable are high;
2. rotation is required, and the stability requirement on the liquid in the measuring process is high.
In summary, in the case of using ambient white light as a light source, the existing abbe refractometer has a chromatic dispersion phenomenon, is difficult to determine a semi-negative line, is limited by a critical refraction angle of a glass refractive index, and has a measurement range of the refractive index limited to 1.3 to 1.7; the existing Mach-Zehnder interferometer has higher requirements on rotation stability and angle precision of an electric control turntable because angle measurement is a main source of uncertainty, and has higher requirements on stability of liquid in the measurement process.
Disclosure of Invention
The invention aims to solve the problems that the existing Abbe refractometer and Mach-Zehnder interferometer have defects and deficiencies when the liquid refractive index is measured, and further provides a transparent liquid concentration measuring device based on the double wedge interferometer and the Mach-Zehnder interferometer.
The technical scheme adopted by the invention for solving the problems is as follows: the invention comprises a first reflecting mirror, a shell, a beam splitting and combining system, an optical platform, a CCD camera, an attenuation sheet, a laser frame, a sample cell, a second reflecting mirror and a beam expanding mirror;
the shell is a box body with an opening at the top, the optical platform is arranged in the shell, the lower surface of the optical platform is parallel to the bottom surface in the shell, the laser is arranged on the upper surface of the optical platform through the laser frame, the first reflecting mirror, the beam splitting and combining system, the CCD camera, the attenuation sheet, the second reflecting mirror and the beam expanding mirror are all arranged on the upper surface of the optical platform, the light beam incident surface of the second reflecting mirror faces towards the light beam emitting opening of the laser, the light beam emitting surface of the second reflecting mirror faces towards the light beam incident opening of the beam expanding mirror, the light beam emitting surface of the beam expanding mirror faces towards the light beam incident surface of the first reflecting mirror, the light beam emitting surface of the first reflecting mirror faces towards the light beam incident opening of the beam splitting and combining system, the sample cell is arranged in the beam splitting and combining system, the light beam emitting opening of the beam splitting and combining system faces towards one side of the attenuation sheet, and the camera lens of the CCD camera faces towards the other side of the attenuation sheet;
the sample cell is a double-wedge sample cell, the sample cell comprises a rectangular groove body, a central partition board and a partition wall, the central partition board is arranged in the rectangular groove body along the diagonal line of the rectangular groove body, the central partition board divides the rectangular groove body into two right-angle triangular groove bodies, one right-angle triangular groove body is a standard liquid B area, the partition wall is arranged on the other right-angle triangular groove body, and the partition wall divides the other right-angle triangular groove body into a standard liquid A area and a solution area to be measured.
Further, the rectangular groove body, the central partition plate and the partition wall are all made of transparent optical glass.
Further, the beam splitting and combining system comprises a beam splitting prism, a third reflector, a one-dimensional moving table, a beam combining prism and a fourth reflector;
the beam splitting prism, the third reflector, the one-dimensional moving table and the fourth reflector are all arranged on the upper surface of the optical platform, the beam combining prism is arranged on the one-dimensional moving table, the beam incident opening of the beam splitting prism faces the beam emergent surface of the first reflector, one beam emergent surface of the beam splitting prism faces the beam incident surface of the fourth reflector, the beam emergent surface of the fourth reflector faces the beam incident surface of the beam combining prism, the other beam emergent surface of the beam splitting prism faces the beam incident opening of the sample cell, the beam incident surface of the third reflector faces the beam emergent opening of the sample cell, the beam emergent surface of the third reflector faces the beam incident surface of the beam combining prism, and the beam emergent surface of the beam combining prism faces one side of the attenuation sheet.
Further, the transparent liquid concentration measuring device based on the double wedge and the Mach-Zehnder interferometer further comprises a protective cover, and the protective cover is arranged at the opening of the shell.
Further, the protection cover is composed of two transparent cover bodies, the two cover bodies are symmetrically arranged, and the outer edge of each cover body is rotationally connected with the end edge of the opening of the shell.
Furthermore, the protective cover is made of transparent materials.
Further, the laser is a helium-neon laser.
The beneficial effects of the invention are as follows: the method is used for measuring the solution concentration, the split angle theta and the included angle of glass groove assembly and the included angle of front and rear surfaces of glass carried by the Mach-Zehnder interferometer are not required to be directly measured, the temperature is not required to be measured or the experimental condition is ensured to be constant, the wavelength of a light source is not required to be known in advance, the gradient of the refractive index concentration relation is not required to be known, and the linear relation between the split angle theta and the included angle of the glass groove assembly and the included angle of the front and rear surfaces of the glass are only required to be ensured to be better, so that the method has remarkable superiority and simplicity compared with the existing scheme; the uncertainty of the solution solubility is 0.5%, the absolute error of the solution concentration measurement is about 0.2-0.6%, when CCD with the horizontal drawing of 1280 multiplied by 5.2 μm is used, the proper fringe spacing is about 56-160 pixels, the concentration is corresponding to the concentration, sodium chloride solution is taken as an example, and the concentration range suitable for measurement is n 2 ±15％(n 2 Is the concentration of standard solution B); the invention is tested at different temperatures, and the refractive index difference is basically consistent and the concentration is basically consistent. The explanation excludes the influence of temperature; the invention has simple and convenient use and high speed, and can finish the measurement of the concentration of one solution within 10 seconds.
Drawings
FIG. 1 is a schematic view of the overall structure of the present invention;
FIG. 2 is a schematic diagram of the structure of a sample cell;
FIG. 3 is a schematic diagram of an equivalent wedge;
FIG. 4 is an equivalent light path diagram;
FIG. 5 is a schematic diagram of pixel coordinates and gray scale;
FIG. 6 is a gray peak schematic;
FIG. 7 is a schematic diagram of the slope obtained by fitting a straight line;
fig. 8 is a flow diagram of joint communication of image processing software and camera driver software.
Detailed Description
The first embodiment is as follows: referring to fig. 1, the transparent liquid concentration measuring device based on the double wedge and mach-zehnder interferometer according to the present embodiment includes a first reflecting mirror 1, a housing 3, a beam splitting and combining system, an optical platform 4, a CCD camera 8, an attenuation sheet 9, a laser 10, a laser frame 12, a sample cell 13, a second reflecting mirror 15, and a beam expander 16;
the shell 3 is a box body with an opening at the top, the optical platform 4 is arranged in the shell 3, the lower surface of the optical platform 4 is parallel to the bottom surface in the shell 3, the laser 10 is arranged on the upper surface of the optical platform 4 through the laser frame 12, the first reflecting mirror 1, the beam splitting and combining system, the CCD camera 8, the attenuation sheet 9, the second reflecting mirror 15 and the beam expanding mirror 16 are all arranged on the upper surface of the optical platform 4, the light beam incident surface of the second reflecting mirror 15 faces the light beam emitting opening of the laser 10, the light beam emitting surface of the second reflecting mirror 15 faces the light beam incident opening of the beam expanding mirror 16, the light beam emitting opening of the beam expanding mirror 16 faces the light beam incident surface of the first reflecting mirror 1, the light beam emitting surface of the first reflecting mirror 1 faces the light beam incident opening of the beam splitting and combining system, the sample cell 13 is arranged in the beam splitting and combining system, the light beam emitting opening of the beam splitting and combining system faces one side of the attenuation sheet 9, and the image pickup lens of the CCD camera 8 faces the other side of the attenuation sheet 9;
the sample cell 13 is a double-wedge sample cell, the sample cell 13 is composed of a rectangular cell 1301, a central partition plate 1302 and a partition wall 1303, the central partition plate 1302 is arranged in the rectangular cell 1301 along the diagonal line of the rectangular cell 1301, the central partition plate 1302 divides the rectangular cell 1301 into two right-angle triangular cells, one right-angle triangular cell is a standard solution B area 1304, the partition wall 1303 is arranged in the other right-angle triangular cell, and the partition wall 1303 divides the other right-angle triangular cell into a standard solution A area 1305 and a solution area 1306 to be measured.
In the present embodiment, the CCD camera 8 is arranged at the other side of the attenuation sheet 9; and removing the imaging lens, and directly irradiating the photosensitive element by the light beam to obtain a gray image, so that preparation is made for further machine vision.
The computer software and the camera driving software are used for joint communication, the pictures are directly read into the software, the grey processing is carried out, and N rows are selected.
Firstly, looking at the first row, drawing a light intensity and abscissa distribution curve in the row, and reversing the color because dark stripes are more obvious than bright stripes, namely, the lower the light intensity is, the larger the gray is. There are n (gray scale) intensity peaks in total, i.e. n fringes. For each gray peak, a gray centroid position is calculated, and p pixels are in the h peak: x is x 1h1 ,x 1h2 ,x 1h3 ,…,x 1hp The gray value is g 1h1 ,g 1h2 ,g 1h3 ,…,g 1hp The gray centroid position is given by equation (2):
gray scale centroid coordinates x 1 :x 11 ,x 12 ,x 13 ,…,x 1n Namely the position of the stripe and the number of stripe stages k 1 :k 11 ,k 12 ,k 13 ,…,k 1n And stripe position x 1 The two satisfy the linear relation:
ε 1 as disturbance term, slope is fringe spacing D 1 ，b 1 Are variables that are not relevant to the experiment and are not considered. Both are linearly fitted by the least squares method, the results are given by equations (4) and (5).
Similarly, the pitch D obtained for the above N rows 1 ,D 2 ,D 3 ,…,D N Taking average value D, D is stripe interval.
The measurement principle is shown in fig. 5, 6 and 7.
The second embodiment is as follows: referring to fig. 1, the embodiment of the present invention is described with reference to the case where the rectangular groove 1301, the center diaphragm 1302, and the partition wall 1303 of the transparent liquid concentration measuring apparatus according to the present embodiment are made of transparent optical glass.
And a third specific embodiment: referring to fig. 1, the beam splitting and combining system of the transparent liquid concentration measuring device according to the present embodiment includes a beam splitting prism 2, a third mirror 5, a one-dimensional moving stage 6, a beam combining prism 11, and a fourth mirror 14;
the beam splitting prism 2, the third reflector 5, the one-dimensional moving table 6 and the fourth reflector 14 are all installed on the upper surface of the optical platform 4, the beam combining prism 11 is installed on the one-dimensional moving table 6, the beam incident opening of the beam splitting prism 2 faces the beam incident surface of the first reflector 1, one beam incident surface of the beam splitting prism 2 faces the beam incident surface of the fourth reflector 14, the beam incident surface of the fourth reflector 14 faces the beam incident surface of the beam combining prism 11, the other beam incident surface of the beam splitting prism 2 faces the beam incident opening of the sample cell 13, the beam incident surface of the third reflector 5 faces the beam incident opening of the sample cell 13, and the beam incident surface of the third reflector 5 faces the beam incident surface of the beam combining prism 11, and the beam incident surface of the beam combining prism 11 faces one side of the attenuation sheet 9. Other components and connection relationships are the same as those of the first embodiment.
The specific embodiment IV is as follows: the transparent liquid concentration measuring device based on the double-wedge and mach-zehnder interferometer according to the present embodiment further includes a protective cover 7, where the protective cover 7 is mounted at an opening of the housing 3, with reference to fig. 1. Other components and connection relationships are the same as those of the first embodiment.
Fifth embodiment: referring to fig. 1, the protection cover 7 of the transparent liquid concentration measuring device based on the double wedge and mach-zehnder interferometer according to the present embodiment is composed of two transparent cover bodies, the two cover bodies are symmetrically arranged, and the outer edge of each cover body is rotationally connected with the end edge of the opening of the housing 3. Other compositions and connection relationships are the same as those of the fourth embodiment.
Specific embodiment six: the description will be given of the present embodiment with reference to fig. 1, in which the protective cover 7 of the transparent liquid concentration measuring device according to the present embodiment is made of a transparent material. Other compositions and connection relationships are the same as those of the fourth embodiment.
Seventh embodiment: the laser 10 of the transparent liquid concentration measuring device according to the present embodiment, which is based on the double wedge and mach-zehnder interferometer, is a helium-neon laser, described with reference to fig. 1. Other components and connection relationships are the same as those of the first embodiment.
Principle of operation
Double wedge sample cell measurement principle:
placing a standard solution A, a standard solution B and a solution to be measured in a standard solution A area 1305, a standard solution B area 1304 and a solution to be measured area 1306 respectively; let the refractive index of the standard solution A be n 1 The refractive index of the standard solution B is n 2 The refractive index of the liquid to be measured is n 3 The thickness of the sample cell is D, and the included angle between the central partition plate and the glass windows on two sides is theta.
When the laser is perpendicularly incident, the emergent light is approximately considered to be parallel to the incident light, and the standard liquid A are selected to pass throughOne ray of quasi-liquid B has a distance x from the edge of the sample cell 1 As shown in FIG. 2, the optical path difference DeltaL is caused by the liquid between the light and the other arm which is not placed in the sample cell Liquid 1 The method comprises the following steps:
similarly, selecting a distance x from the edge of the sample cell 2 The optical path difference delta L is caused by the liquid between the light passing through the liquid to be measured and the standard liquid B and the other arm which is not placed in the sample cell Liquid 2 The method comprises the following steps:
due to Dn in the formulas (6) and (7) 2 The distance between interference fringes is not affected, so that the left and right groups of double wedges can be equivalently added with the angle theta and the refractive index n on the two sides of the partition board 1 -n 2 And n 3 -n 2 Is included.
Meanwhile, the factors of the split angle, the non-parallel front and rear surfaces of the glass window, the equivalent split angle introduced by the non-parallel assembly of the front and rear glass windows and the like of the Mach-Zehnder interferometer are considered, and all the factors can be summarized as the equivalent split angle theta 0 An air wedge with a refractive index of 1, then the double wedge may be equivalent to a three wedge device as shown in fig. 3. At this time, the optical path in the mach-zehnder interferometer may be equivalent to the optical path shown in fig. 4;
at this time, the optical path difference delta L between one arm of the sample cell and the reference arm through two laser beams of the standard liquid A-B and the liquid to be measured-the standard liquid B 1 And DeltaL 2 The method comprises the following steps of:
ΔL 1 ＝x 1 [(n 1 -n 2 )tanθ+tanθ 0 ]+Dn 2 (8)
ΔL 2 ＝x 2 [(n 3 -n 2 )tanθ+tanθ 0 ]+Dn 2 (8)
as can be seen from equations (8) and (9) and the interference condition Δl=kλ, two sets of interference fringes are formed with the sample cell partition wall as a boundary, and the fringe pitches are respectively:
from formulae (10) and (11):
if the laser wavelength and the included angle between the central partition board and the glass at two sides are known to be theta, the stripe interval D at two sides of the partition wall is measured 1 And D 2 And (3) measuring the refractive index difference between the liquid to be measured and the standard liquid A by using the method (12), and further obtaining the refractive index and the concentration of the liquid to be measured. The use of (12) to measure the refractive index of a transparent liquid has the following advantages:
1. the splitting angles introduced by the Mach-Zehnder interferometer itself, such as the splitting angle, the glass window and the like, are all reduced to equivalent splitting angle theta 0 And formula (12) does not contain θ 0 I.e. the scheme naturally eliminates theta 0 Is a function of (1);
2. the refractive index of the standard liquid B determines the range of the refractive index of the liquid measured by the experimental device, and the refractive index n of the standard liquid B is not required when the (12) type calculation is utilized in the measuring range 2 In the experiment, only a solution with known concentration is used as the standard solution A.
Summarizing the general formula (13) according to the relation (13) between the refractive index, the concentration and the temperature
n(T,c)＝k 1 c+k 2 T (13)
Wherein k is 1 And k is equal to 2 Is a constant independent of both temperature T and concentration c.
The relationship between refractive index difference and concentration difference is obtained from formula (13):
n 3 -n 1 ＝(k 1 c 3 +k 2 T)-(k 1 c 1 +k 2 T)＝k 1 (c 3 -c 1 ) (14)
the coefficient k is obtained by looking up a table 1 Concentration difference is obtained from the refractive index difference, and concentration measurement is realized.
In order to solve the above problems, angle scaling can be performed according to the following principle:
substituting formula (14) into (12) yields:
using a liquid standard liquid C with known concentration to replace the liquid to be measured, wherein the refractive index is n 30 Known concentration is c 30 The space between the stripes formed on the left and right sides of the partition wall is D 30 And D 10 Substituting the refractive index into the glass tube (15) to reversely determine the relation slope k between the included angle tan theta between the central partition board and the glass on both sides and the refractive index 1 Is the product of (1), namely:
substituting formula (16) into (15) yields:
deforming to obtain the concentration difference c between the liquid to be measured and the standard liquid A 3 -c 1 Finally, the concentration of the liquid to be measured is obtained:
examples
The effect of the invention is evaluated by measuring sodium chloride solution as follows:
table 1 sodium chloride solution measurement
(standard solution B concentration is 0%)
Uncertainty of 0.5%
The absolute error of the solution concentration measurement is about 0.2 to 0.6 percent
When a CCD having a horizontal frame of 1280×5.2 μm is used, a suitable stripe pitch is preferably about 56 to 160 pixels, and a suitable measuring range of the concentration is n 2 ±15％(n 2 Is the concentration of standard solution B
The measurements were performed at different temperatures and measured to have substantially uniform refractive index differences and substantially uniform concentrations. The description excludes the effect of temperature.
The use is simple and convenient, the speed is high, and the measurement of the concentration of one solution can be completed within 10 seconds.
The present invention is not limited to the preferred embodiments, but is capable of modification and variation in detail, and other embodiments, such as those described above, of making various modifications and equivalents will fall within the spirit and scope of the present invention.
Claims (6)
1. The transparent liquid concentration measuring device based on the double wedge and Mach-Zehnder interferometer comprises a first reflecting mirror (1), a shell (3), a beam splitting and combining system, an optical platform (4), a CCD camera (8), an attenuation sheet (9), a laser (10), a laser frame (12), a sample cell (13), a second reflecting mirror (15) and a beam expanding mirror (16);
the shell (3) is a box body with an opening at the top, the optical platform (4) is arranged in the shell (3), the lower surface of the optical platform (4) is parallel to the bottom surface in the shell (3), the laser (10) is arranged on the upper surface of the optical platform (4) through the laser frame (12), the first reflecting mirror (1), the beam splitting and combining system, the CCD camera (8), the attenuation sheet (9), the second reflecting mirror (15) and the beam expanding mirror (16) are all arranged on the upper surface of the optical platform (4), the beam incident surface of the second reflecting mirror (15) faces the beam emitting opening of the laser (10), the beam emitting surface of the second reflecting mirror (15) faces the beam incident opening of the beam expanding mirror (16), the beam emitting surface of the beam expanding mirror (16) faces the beam incident surface of the first reflecting mirror (1), the beam emitting surface of the first reflecting mirror (1) faces the beam splitting and combining system, the sample cell (13) is arranged in the beam splitting and combining system, the beam incident surface of the beam splitting and combining system faces the other side of the CCD camera (9) of the beam splitting and combining system; the method is characterized in that:
the sample cell (13) is a double-wedge sample cell, the sample cell (13) is composed of a rectangular groove body (1301), a central partition board (1302) and a partition wall (1303), the central partition board (1302) is arranged in the rectangular groove body (1301) along the diagonal line of the rectangular groove body (1301), the central partition board (1302) divides the rectangular groove body (1301) into two right-angle triangular groove bodies, one right-angle triangular groove body is a standard liquid B area (1304), the partition wall (1303) is arranged on the other right-angle triangular groove body, and the partition wall (1303) divides the other right-angle triangular groove body into a standard liquid A area (1305) and a solution area (1306) to be measured;
the beam splitting and combining system comprises a beam splitting prism (2), a third reflector (5), a one-dimensional mobile station (6), a beam combining prism (11) and a fourth reflector (14);
the beam splitting prism (2), the third reflector (5), the one-dimensional moving table (6) and the fourth reflector (14) are all installed on the upper surface of the optical platform (4), the beam combining prism (11) is installed on the one-dimensional moving table (6), the beam incident opening of the beam splitting prism (2) faces the beam incident surface of the first reflector (1), one beam incident surface of the beam splitting prism (2) faces the beam incident surface of the fourth reflector (14), the beam incident surface of the fourth reflector (14) faces the beam incident surface of the beam combining prism (11), the other beam incident surface of the beam splitting prism (2) faces the beam incident opening of the sample cell (13), the beam incident surface of the third reflector (5) faces the beam incident surface of the beam combining prism (11), and the beam incident surface of the beam combining prism (11) faces one side of the attenuation sheet (9).
2. The transparent liquid concentration measurement device based on the double wedge and mach-zehnder interferometer according to claim 1, wherein: the rectangular groove body (1301), the central partition plate (1302) and the partition wall (1303) are all made of transparent optical glass.
3. The transparent liquid concentration measurement device based on the double wedge and mach-zehnder interferometer according to claim 1, wherein: the transparent liquid concentration measuring device based on the double wedge and Mach-Zehnder interferometer further comprises a protective cover (7), and the protective cover (7) is arranged at the opening of the shell (3).
4. The transparent liquid concentration measurement device based on the double wedge and mach-zehnder interferometer according to claim 3, wherein: the protection cover (7) consists of two transparent cover bodies, the two cover bodies are symmetrically arranged, and the outer edge of each cover body is rotationally connected with the end edge of the opening of the shell (3).
5. The transparent liquid concentration measurement device based on the double wedge and mach-zehnder interferometer according to claim 3, wherein: the protective cover (7) is made of transparent materials.
6. The transparent liquid concentration measurement device based on the double wedge and mach-zehnder interferometer according to claim 1, wherein: the laser (10) is a helium-neon laser.
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| CN101149343A (en) * | 2007-11-14 | 2008-03-26 | 哈尔滨工业大学 | 4f phase coherent imaging device based on michelson interferometer |
| JP4997406B1 (en) * | 2011-06-16 | 2012-08-08 | レーザーテック株式会社 | Shape measuring device, depth measuring device and film thickness measuring device |
| CN213633169U (en) * | 2020-11-11 | 2021-07-06 | 温州大学 | Experimental device for measure liquid refracting index |
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| US20110317170A1 (en) * | 2006-02-22 | 2011-12-29 | Yung-Chieh Hsieh | Wedge pair for phase shifting |
| JP5660514B1 (en) * | 2013-12-04 | 2015-01-28 | レーザーテック株式会社 | Phase shift amount measuring apparatus and measuring method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101149343A (en) * | 2007-11-14 | 2008-03-26 | 哈尔滨工业大学 | 4f phase coherent imaging device based on michelson interferometer |
| JP4997406B1 (en) * | 2011-06-16 | 2012-08-08 | レーザーテック株式会社 | Shape measuring device, depth measuring device and film thickness measuring device |
| CN213633169U (en) * | 2020-11-11 | 2021-07-06 | 温州大学 | Experimental device for measure liquid refracting index |
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