CN112285059A - Device for measuring liquid refractive index based on CCD method - Google Patents
Device for measuring liquid refractive index based on CCD method Download PDFInfo
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- CN112285059A CN112285059A CN202011271993.8A CN202011271993A CN112285059A CN 112285059 A CN112285059 A CN 112285059A CN 202011271993 A CN202011271993 A CN 202011271993A CN 112285059 A CN112285059 A CN 112285059A
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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
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/06—Illumination; Optics
- G01N2201/061—Sources
- G01N2201/06113—Coherent sources; lasers
Abstract
The invention relates to an optical precision measuring device, in particular to a device for measuring the refractive index of liquid based on a CCD method. A beam of laser is shot into a measuring container containing a sample to be measured from the diameter direction, and enters the sample to be measured to form a light path after being refracted, the laser is converged at one point of an interface after being refracted by the interface, the width of the two light paths of the laser passing through the sample to be measured and the distance between the two widths are detected, and the refractive index of the liquid is calculated. Compared with the prior art, the invention has the advantages and effects that: the invention can rapidly measure the liquid refractive index in any environment; the measuring device is also suitable for measuring the refractive index of solid, thin film and gas; the measuring device has high measuring precision, wherein the precision of measuring the refractive index of the liquid is 0.0001-0.0010 higher; the measuring device is simple, and the operation and the measuring process are convenient; the measuring device has low price and high cost performance.
Description
Technical Field
The invention relates to an optical precision measuring device, in particular to a device for measuring the refractive index of liquid based on a CCD method.
Background
The refractive index of the liquid is usually measured by an Abbe refractometer, a reading microscope and the like together with an instrument. Although the Abbe refractometer has high measurement accuracy, contact measurement is non-online measurement, which brings inconvenience to production inspection and control, and although a reading microscope can be used for non-contact measurement, the accuracy is not good and has certain limitation. Particularly, when the concentration accuracy requirement in the pharmaceutical industry is high, the ideal requirement is often not met.
The methods for measuring the refractive index of liquid are various, and the laser irradiation method, the optical fiber Young's interference method, the grazing incidence method, the capillary imaging method, the diffraction grating method and the CCD measuring method are mainly introduced below.
Laser irradiation method: the laser irradiation method requires refraction of the liquid and reflection of the surface layer of the liquid when measuring the refractive index. The liquid refractive index is quantitatively tested by using the geometrical relation of light propagation. The refractive index of the liquid is measured using a probability beam at a critical angle. The laser irradiation method has the advantages of simple equipment, low cost and high measurement accuracy, but inaccurate measurement of the spot spacing can reduce the accuracy of the refractive index.
Fiber Young's interference method: the optical fiber Young's interference method uses the optical fiber with small core diameter, uniform light spot and good light transmission as an interference light source, so that the interference pattern is brighter and the fringe is wider, thereby facilitating the measurement. In addition, the method only needs to measure the width of the stripe, and measurement errors are reduced. Although the optical fiber Young's interferometry has high measurement accuracy, the requirement on operation is high, and the optical fiber Young's interferometry is not suitable for wide application.
The grazing surface incidence method is to use Abbe refractometer to measure the refractive index of liquid, and when in use, the refractive index of the liquid to be measured can be directly read from the dial plate only by aligning the cross filament of the telescope with the light and dark boundary line. The grazing incidence method is simple to operate and high in accuracy, but the measuring range of the grazing incidence method is limited.
Capillary imaging method: the capillary filled with transparent liquid is used for forming a cylindrical lens, and based on the imaging principle of a coaxial spherical optical system, the single parameter measurement is carried out on the magnification of the optical imaging system, so that the refractive index of the liquid to be measured is calculated. The capillary tube imaging method is suitable for accurate and rapid measurement of the refractive index of the trace liquid.
CCD measurement: the refractive index of the liquid is calculated by CCD measurement using the relationship between the refractive index of the liquid and the amount of deviation. The refractive index of the liquid is obtained through data measurement and calculation, the CCD can measure the numerical value very accurately, and slight change can be observed, so that certain experimental precision is achieved.
Therefore, a refractive index measuring method with simple and convenient operation and high measuring precision is urgently needed.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a method for measuring the refractive index of liquid.
Another object of the present invention is to provide an application of the above method for measuring refractive index of liquid.
The utility model provides a device for measuring liquid refracting index based on CCD method, includes electron microscope, laser emitter, support, scale and measures the container, its characterized in that:
a beam of laser is injected into a measuring container containing a sample to be measured from the diameter direction, enters the sample to be measured to form a light path after being refracted, is refracted by an interface, and is converged at one point of the interface, and the width of the two light paths of the laser passing through the sample to be measured and the distance between the two widths are detected;
respectively measuring the widths of two light paths under a sample to be measured and the distance between the two widths in an electron microscope through the step (1), and substituting the widths into a formula A to calculate the refractive index of the sample to be measured;
obtaining the refractive index of a sample body to be detected in monochromatic light through the steps (1) and (2);
the formula A is as follows:
wherein nx is the refractive index of the sample to be measured, r is the radius of the measuring container, d is the radius width of the laser, d1 and d2 are respectively the longer light path width and the shorter light path width, and L is the vertical distance of the two light path widths.
The measuring container in the step (1) is a perfect circle.
The laser emitter emits laser light with wavelength of 655nm and radius of 3 mm.
The electron microscope is DY-10A, and the resolution is 1980 x 1080.
The sample in the step (1) is liquid, solid or film, the sample to be detected in the step (2) is liquid, solid or film, and the optical path in the step (2) is clear and has a clear visible boundary.
The polyethylene container with the refractive index of the measurement container in the step (1) being n = 1.0000.
The method is applied to measuring the refractive index of a sample.
Compared with the prior art, the invention has the advantages and effects that: the invention can rapidly measure the liquid refractive index in any environment; the measuring device is also suitable for measuring the refractive index of solid, thin film and gas; the measuring device has high measuring precision, wherein the precision of measuring the refractive index of the liquid is 0.0001-0.0010 higher; the measuring device is simple, and the operation and the measuring process are convenient; the measuring device has low price and high cost performance.
Drawings
FIG. 1 is a flow chart of a measurement method of the present invention;
FIG. 2 is a schematic optical path diagram of the measurement principle of the present invention;
FIG. 3 is an enlarged detail view of the optical path diagram of the measurement principle of the present invention;
FIG. 4 is a schematic view of a measuring apparatus and a light path diagram provided in embodiment 1 of the present invention;
FIG. 5 is a schematic view of a measuring apparatus and a light path diagram provided in embodiment 2 of the present invention;
FIG. 6 is a graph showing the refractive index of an olive oil solution in example 1 of the present invention;
FIG. 7 is a graph of the refractive index of a corn oil solution in accordance with example 2 of the present invention.
Detailed Description
The flow of measuring the refractive index of the liquid is shown in fig. 1, and specifically comprises the following steps: a beam of laser is shot into a measuring container containing a sample to be measured from the diameter direction, enters the sample to be measured to form a light path after being refracted, is converged at one point of an interface after being refracted by the interface, detects the width of the two light paths of the laser passing through the sample to be measured and the distance between the two widths, and calculates the refractive index of the sample to be measured according to a formula A.
The principle analysis of the method of the invention is as follows:
as shown in figure 2, laser is injected from the diameter direction, the width of the laser is d, the included angle between the normal line and the diameter is made to be less than 1, the laser enters liquid and then is refracted, and the included angle between the normal line and the refracted light is made to be less than 2. The path widths of the laser light in the transparent liquid are d1 and d2, respectively, and the vertical distance between d1 and d2 is L. The distance d can be known from laser parameters, and d1 and d2 can be accurately measured by a CCD. The radius of the culture dish is r, and the radius width of the laser is d; the refractive index of air is approximately 1 and the refractive index of liquid is nx.
From the refractive index formula of light:
the geometrical relationship shows that:
from (1), (4) and (5), (6):
in the process of measuring the refractive index by using the method, after the test system is well adjusted, the instrument operation steps are as follows:
(1) adjusting the CCD, firstly turning on a power supply, connecting the USB of the CCD with a computer, turning on computer camera software S-EYE, selecting a camera in camera options, selecting resolution 1980 x 1080 in preview, adjusting the CCD to a proper height, adjusting an eyepiece, and focusing according to a picture to achieve the highest definition.
(2) And (4) calibration, namely selecting measurement in S-EYE software, clicking an editing column to input a required name, putting an object (a ruler, a calibration piece and the like) with a known size into a CCD (charge coupled device) dosage range to enable the object to be in the center of a picture, dragging the ruler in the software to calibrate, and completing calibration and clicking new addition.
(3) Measuring the refractive index of the liquid to be measured, placing the liquid to be measured in a visual field, adjusting laser incidence to enable the center of the CCD to have a clear visible light path, and respectively measuring d1, d2 and L according to the graph shown in figure 1, wherein L2 can measure the distance from the calibrated S-EYE.
(4) And calculating the refractive index of the sample to be measured, substituting the measured d1, d2 and L into a formula A to obtain the refractive index of the sample to be measured, repeating the steps for multiple times, repeating the 3-5 experiments to obtain data, and calculating to obtain the refractive index nx.
The method for measuring the liquid refractive index based on the CCD method is applied to the measurement of the sample refractive index.
The samples include liquids, solids and films.
A device for measuring the liquid refractive index based on a CCD method is designed by the method and comprises a laser, an electron microscope, a measuring container and a bracket; from top to bottom, the electron microscope, the support, the measuring container is arranged in proper order, and the laser passes through in measuring container's diameter, and measuring container is located electron microscope field of vision center, and measuring container is used for holding the sample that awaits measuring.
The present invention will be described in further detail with reference to examples and drawings, but the embodiments of the present invention are not limited thereto.
Example 1
A device for measuring the refractive index of liquid based on a CCD method is shown in figure 4 and comprises a laser emitter 1, a measuring container 3, a bracket, a scale and an electron microscope 4.
The light path adjusting process of the device is as follows:
laser is injected along the diameter of the measuring container, enters a sample to be measured to form a light path 2 after being refracted, is refracted by an interface and converged at one point of the interface, and the light intensity is adjusted to form a clear visible light path.
The specific measurement steps of the device are as follows:
(1) adjusting the CCD: firstly, a power supply is turned on, a USB of the CCD is connected with a computer, computer shooting software S-EYE is turned on, a camera is selected from camera options, resolution 1980 x 1080 is selected from preview, the CCD is adjusted to be in a proper height, an eyepiece is adjusted, and focusing is carried out according to pictures so as to achieve the highest definition.
(2) Calibration: selecting measurement in S-EYE software, clicking in a calibration column to edit and input a required name, putting an object (ruler, standard part, etc.) with a known size into a CCD (charge coupled device) dosage range to enable the object to be in the center of a picture, dragging a ruler in the software to calibrate, and completing calibration and clicking newly adding.
(3) Measurement of refractive index of olive oil: the measuring container containing olive oil is placed in the visual field, laser incidence is adjusted to enable a clear visible light path to appear at the center of the CCD, and distances d1, d2 and L are respectively measured according to the graph shown in figure 1, wherein L2 can be measured by calibrated S-EYE. At this time, d1, d2 and L were recorded.
(4) And calculating the refractive index of the sample to be measured, substituting the measured d1, d2 and L into a formula A to obtain the refractive index of the olive oil, measuring for multiple times, repeating the steps, repeating the 3-5 experiments to obtain data, and calculating to obtain the refractive index nx.
(5) The refractive index of olive oil measured by Abbe refractometer is taken as a standard, and the result is shown in FIG. 6: the surface of the measuring device and the measuring method provided by the embodiment are very close to the detection result of a common Abbe refractometer, and the relative error is within 0.1 percent.
Example 2
The device provided by the embodiment is different from the device provided by the embodiment 1 in that: the liquid samples differed, i.e., olive oil was changed to corn oil.
The refractive index of corn oil measured by Abbe refractometer was used as a standard, and the results are shown in FIG. 7: the surface of the measuring device and the measuring method provided by the embodiment are very close to the detection result of a common Abbe refractometer, and the relative error is also within 0.1 percent.
In short, the specific structure of the present invention is various, and any device that uses a beam of monochromatic light to inject into a perfect circle measuring container and measures the refractive index of the sample to be measured by detecting the parameters of the light path in the solution belongs to the protection scope of the present application.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention and are equivalent to the replacement of the above embodiments are included in the scope of the present invention.
Claims (7)
1. The utility model provides a device for measuring liquid refracting index based on CCD method, includes electron microscope, laser emitter, support, scale and measures the container, its characterized in that:
a beam of laser is injected into a measuring container containing a sample to be measured from the diameter direction, enters the sample to be measured to form a light path after being refracted, is refracted by an interface, and is converged at one point of the interface, and the width of the two light paths of the laser passing through the sample to be measured and the distance between the two widths are detected;
respectively measuring the widths of two light paths under a sample to be measured and the distance between the two widths in an electron microscope through the step (1), and substituting the widths into a formula A to calculate the refractive index of the sample to be measured;
obtaining the refractive index of a sample body to be detected in monochromatic light through the steps (1) and (2);
the formula A is as follows:
wherein nx is the refractive index of the sample to be measured, r is the radius of the measuring container, d is the radius width of the laser, d1 and d2 are respectively the longer light path width and the shorter light path width, and L is the vertical distance of the two light path widths.
2. The device for measuring the refractive index of liquid based on the CCD method according to claim 1, wherein: the measuring container in the step (1) is a perfect circle.
3. The device for measuring the refractive index of liquid based on the CCD method according to claim 1, wherein: the laser emitter emits laser wavelength of 655nm and radius of 3 mm.
4. The device for measuring the refractive index of liquid based on the CCD method according to claim 1, wherein: the model of the electron microscope is DY-10A, and the resolution is 1980 x 1080.
5. The device for measuring the refractive index of liquid based on the CCD method according to claim 1, wherein:
the sample in the step (1) is liquid, solid or film, the sample to be detected in the step (2) is liquid, solid or film, and the optical path in the step (2) is clear and has clear visible boundaries.
6. The device for measuring the refractive index of liquid based on the CCD method according to claim 2, wherein: the polyethylene container with the refractive index of the measurement container in the step (1) being n = 1.0000.
7. The device for measuring the liquid refractive index based on the CCD method according to any one of claims 1 to 6, which is applied to the measurement of the sample refractive index.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011271993.8A CN112285059A (en) | 2020-11-14 | 2020-11-14 | Device for measuring liquid refractive index based on CCD method |
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| CN202011271993.8A CN112285059A (en) | 2020-11-14 | 2020-11-14 | Device for measuring liquid refractive index based on CCD method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113252603A (en) * | 2021-04-16 | 2021-08-13 | 清华大学 | Optimal refractive index measurement method of multilayer transparent ball bed |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101082577A (en) * | 2007-07-06 | 2007-12-05 | 云南大学 | Method for accurate measuring trace quantity liquid refractivity |
| CN101701912A (en) * | 2009-11-16 | 2010-05-05 | 云南大学 | Method for nondestructive measurement of refractive index of transparent capillary wall and device thereof |
| CN102749303A (en) * | 2012-07-14 | 2012-10-24 | 浙江师范大学 | Device and method for measuring refractive index of flat plate type transparent medium |
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- 2020-11-14 CN CN202011271993.8A patent/CN112285059A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101082577A (en) * | 2007-07-06 | 2007-12-05 | 云南大学 | Method for accurate measuring trace quantity liquid refractivity |
| CN101701912A (en) * | 2009-11-16 | 2010-05-05 | 云南大学 | Method for nondestructive measurement of refractive index of transparent capillary wall and device thereof |
| CN102749303A (en) * | 2012-07-14 | 2012-10-24 | 浙江师范大学 | Device and method for measuring refractive index of flat plate type transparent medium |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113252603A (en) * | 2021-04-16 | 2021-08-13 | 清华大学 | Optimal refractive index measurement method of multilayer transparent ball bed |
| CN113252603B (en) * | 2021-04-16 | 2022-03-01 | 清华大学 | Optimal refractive index measurement method of multilayer transparent ball bed |
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