Alcohol concentration measuring device based on grazing incidence method

Abstract

The utility model discloses an alcohol concentration measuring device based on a grazing incidence method in the field of solubility detection devices, which comprises a light source for emitting light for testing; an optical device arranged on an optical path of the light emitted by the light source and converging the light; the light splitting body is arranged on the rear side of the optical device, the focus of the light converged by the optical device passes through the interior of the light splitting body, and the light passing through the light splitting body is dispersed; an optical signal reception processing unit for detecting light passing through the spectroscope; during use, test liquid is added into the light splitting body, after light enters and penetrates through the liquid at a fixed point, grazing incidence and emergent light angles are both within critical angles, a view field with a light and shade boundary, namely a half-shade view field, is formed on the light splitting body by taking the critical angles as a boundary, and the view field can be captured by the light signal receiving and processing part; the semi-shade view field is not influenced by bubbles and impurities in the solution and is only related to the boundary, so that the requirement on a sample is low, and the detection precision is ensured.

Description

Technical Field

[0001] The present application relates to the technical field of liquid solubility detection devices, and in particular to an alcohol concentration measurement device based on a grazing incidence method. Background Art

[0002] Alcohol and water have different refractive indices. Within a certain concentration range, there is a linear relationship between alcohol concentration and the refractive index of the alcohol solution. This property allows accurate measurement of the concentration of alcohol solutions by measuring the refractive index. Refractive index measurements generally rely on the refractive properties of light. Common measurement methods include the minimum deflection angle method, the total reflection method, and grazing incidence methods. Because refractive index measurements can achieve high accuracy, high-precision refractive index measurements have become an effective method for identifying material composition, determining purity and concentration, and assessing material quality. In practical applications, the minimum deflection angle method requires the sample to be processed into a prism shape and is generally used to measure solid samples. The refractometer method generally utilizes the total internal reflection of light at two interfaces to measure refractive index. Its measurement accuracy depends on the accuracy of the position of the semi-shaded field of view after total internal reflection. This accuracy is affected by factors such as the monochromaticity of the incident light, the degree of interface wetting, the dispersion characteristics of the reflected interface, and the accuracy of the detector displacement measurement. Professional high-precision refractometers are expensive and complex to operate, requiring professional operation and analysis. Most refractometers have high requirements for the sample quality, and impurities and bubbles may affect the measurement results. Utility Model Content

[0003] The purpose of this application is to provide an alcohol concentration measuring device based on the grazing incidence method to solve the defects in the prior art that most refractometers have high requirements for the sample itself, impurities and bubbles may affect the measurement results, and the detection accuracy cannot be guaranteed.

[0004] To solve the above technical problems, this application is implemented by adopting the following technical solutions:

[0005] An alcohol concentration measuring device based on grazing incidence method, comprising

[0006] a light source that emits the light used for testing;

[0007] an optical device arranged on an optical path of the light emitted by the light source and converging the light;

[0008] A beam splitter is arranged at the rear side of the optical device, wherein the focus of light converged by the optical device passes through the inside of the beam splitter and disperses the light passing through the beam splitter;

[0009] The optical signal receiving and processing unit is configured to detect the light passing through the spectrometer.

[0010] In a further embodiment of the present application, the optical device includes a collimating lens and a converging lens that are spaced apart and coaxially arranged. A light-dimming polarizer is provided on the optical path between the collimating lens and the converging lens, and the light-dimming polarizer is movable along the optical path.

[0011] In a further solution, the light-reducing polarizer includes an attenuation plate and a polarizer that are spaced apart and coaxially arranged, and the light passes through the attenuation plate and the polarizer in sequence.

[0012] In a further embodiment of the present application, the beam splitter includes a first prism and a second prism, a light shielding plate is connected between the opposing faces of the first prism and the second prism, and a liquid storage area is formed between the first prism, the second prism and the light shielding plate.

[0013] In a further solution, the shading sheet is U-shaped.

[0014] In a further embodiment of the present application, the optical signal receiving and processing unit includes an optical filter, a charge coupler, and a computer;

[0015] The filter is installed on the side of the charge coupler facing the spectrometer, and the charge coupler is electrically connected to the computer. The light emitted by the spectrometer will appear on the filter and be captured by the charge coupler (CCD). The computer performs calculations based on the relationship between displacement and refractive index.

[0016] In a further solution of the present application, the light source, the optical device, and the center of the beam splitter are coaxially arranged.

[0017] In a further solution of the present application, the light source is an LED light emitting diode, which is inexpensive.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] When the present application is used, a test liquid is added to the spectrometer, and after the light is incident at a fixed point and passes through the liquid, grazing incidence is formed on the spectrometer, and the angles of the outgoing light are all within the critical angle, forming a field of view with a light-dark boundary with the critical angle as the boundary, that is, a semi-shaded field of view, which will be captured by the optical signal receiving and processing unit; the semi-shaded field of view will not be affected by bubbles and impurities in the solution, but is only related to the boundary, and has low requirements for the sample, thereby ensuring detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of an embodiment of the present application;

[0021] Figure 2 Schematic diagram of the principle of generating a half-shaded field of view by a beam splitter at grazing incidence in this application;

[0022] in

[0023] 1. Light source; 2. Collimating lens; 3. Neutral density plate; 4. Polarizer; 5. Condenser lens; 6. First prism; 7. Shade plate; 8. Second prism; 9. Filter; 10. Charge coupler. DETAILED DESCRIPTION

[0024] The following will be combined with the accompanying drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only some embodiments of the present application, rather than all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application, its application, or use.

[0025] Reference Attachment Figure 1 This embodiment discloses an alcohol concentration measuring device based on a grazing incidence method, comprising

[0026] Light source 1, optical device, spectrometer, optical signal receiving and processing unit; light source 1 emits light used for testing; the optical device is arranged on the optical path of the light emitted by light source 1 and converges the light; the spectrometer is arranged on the rear side of the optical device, and the focus of the light converged by the optical device passes through the inside of the spectrometer, and disperses the light passing through the spectrometer; the optical signal receiving and processing unit is used to detect the light passing through the spectrometer, and the light source 1 uses an LED light-emitting diode and generates a white light source.

[0027] The structure of the device is described in detail below;

[0028] Continue to observe the attached Figure 1 The optical device in this embodiment includes a collimating lens 2 and a converging lens 5 arranged at intervals and coaxially. A light-dimming polarizer is provided on the optical path between the collimating lens 2 and the converging lens 5. The light-dimming polarizer is composed of an attenuation plate 3 and a polarizer 4 arranged at intervals and coaxially. Light passes through the attenuation plate 3 and the polarizer 4 in sequence.

[0029] The beam splitter in this embodiment includes a first prism 6 and a second prism 8, and a light shielding plate 7 is connected between the opposite surfaces of the first prism 6 and the second prism 8. A liquid storage area is formed between the first prism 6, the second prism 8 and the light shielding plate 7, and liquid alcohol is contained in the liquid storage area; the light sheet 7 is U-shaped, and the collimating lens 2 and the converging lens 5 use lenses 2 and 5 with a focal length of 50 mm and a diameter of 10 mm, and the angle of the converging light generated is about 18 degrees.

[0030] The optical signal receiving and processing unit in this embodiment includes a filter 9, a charge coupler 10 and a computer; the filter 9 is mounted on the side of the charge coupler 10 facing the spectrometer, and the charge coupler 10 is electrically connected to the computer.

[0031] During use, a white light source is generated by an LED. A collimated light beam is emitted from a collimated lens 2. The light intensity is adjusted by an attenuator 3, and the polarization is altered by a polarizer 4. The beam is then converged by a converging lens 5 and enters the spectroscopic sample cell. The incident light passes through a first prism 6 and is incident on the liquid film at a fixed point, with the focus falling on the interface between the first prism 6 and the liquid surface. The incident light enters the solution at a grazing incidence on a light shield 7, and light below the critical angle is emitted, forming a semi-shaded field of view. The exiting light is then emitted from a second prism 8, enters the optical signal receiving and processing system, and is captured by a CCD 10. A computer then performs calculations based on the relationship between displacement and refractive index.

[0032] Reference Attachment Figure 2 The relationship between displacement and refractive index is:

[0033]

[0034] The refractive index of the two prisms is The refractive index of the liquid to be measured is , the refractive index of air is ,and The incident point A, the shading plate position B (the critical point of light exiting the liquid), and the second prism 8 exit point C. The vertical distance from A to the shading plate 7 is , B is projected on the image screen as O, which is set as the displacement origin. The thickness of the liquid film is , the distance between B and the exit surface of the second prism 8 The exit surface of the second prism 8 is parallel to the image screen and the distance is .

[0035] The computer program calculates the refractive index of the solution to be tested through the relationship between displacement and refractive index, and then calculates the concentration of the solution through the empirical formula of different solution refractive indices and solution concentrations; the prior art will not be described in detail here.

[0036] Next, we will test the alcohol solution with a certain concentration;

[0037] Step 1: Build the device and adjust the optical axis to be horizontal so that the two prisms (first prism 6 and second prism 8) are properly positioned with the CCD to capture the clearest semi-shaded field of view.

[0038] Step 2: At room temperature, prepare pure water and three alcohol solutions of varying concentrations, recording the corresponding alcohol solution concentrations. Use pure water as the reference solution. Inject the three calibration solutions sequentially between the slits of the biprism in ascending concentration order. After the solutions stabilize, record the position of the light-dark boundary and compare it with the position of the reference solution boundary. Use a computer to fit the light-dark boundary displacement versus solution concentration curve using a cubic function to create the calibration curve.

[0039] Step 3: Inject pure water, a reference solution, into the sample tank (the liquid storage area between the first prism 6 and the second prism 8). After the solution stabilizes, record the position of the light-dark boundary.

[0040] Step 4: Pour the test solution into the sample tank. Once the solution stabilizes, record the position of the light / dark boundary of the test solution and compare it with the boundary of the reference solution. The computer then calculates the concentration of the test solution using the calibration curve.

[0041] In summary, the present application relates to a new device for measuring the concentration of an alcohol solution, which uses an LED as a light source 1 with a wide spectrum of incidence and two standard prisms as containers, with low cost, compact structure, and easy miniaturization of the device; uses the grazing incidence method as the main principle of the device, with a simple structure and low requirements for the sample; through improvement measures such as the polarizer 4 and the light-shielding plate 7, the contrast of the semi-shaded field of view is enhanced, and the measurement accuracy is improved; the operation process is simple, the environmental requirements are not high, and it is easy to use.

[0042] It is understood from common technical knowledge that the present application may be implemented by other embodiments that do not deviate from its spirit or essential features. Therefore, the embodiments disclosed above are merely illustrative in all respects and are not intended to be exclusive. All modifications that come within the scope of this application or are equivalent to the scope of this application are intended to be included in this application.

Claims

1. A device for measuring alcohol concentration based on grazing incidence method, characterized in that: include A light source (1) that emits light used for testing; An optical device arranged on the optical path of the light emitted by the light source (1) and focusing the light; A beam splitter is arranged at the rear side of the optical device, and the focus of light gathered by the optical device passes through the inside of the beam splitter, and the light passing through the beam splitter is dispersed; an optical signal receiving and processing unit, which is used to detect the light passing through the spectrometer; The optical device comprises a collimating lens (2) and a converging lens (5) which are spaced apart and coaxially arranged, a light-dimming polarizer being provided on the optical path between the collimating lens (2) and the converging lens (5); the beam splitter comprises a first prism (6) and a second prism (8), a light shielding sheet (7) being connected between the opposing prism faces of the first prism (6) and the second prism (8), and a liquid storage area being formed between the first prism (6) and the second prism (8) and the light shielding sheet (7).

2. The alcohol concentration measuring device based on grazing incidence method according to claim 1 is characterized in that: The light-reducing polarizer comprises an attenuation plate (3) and a polarizer (4) which are spaced apart and coaxially arranged, and the light passes through the attenuation plate (3) and the polarizer (4) in sequence.

3. The alcohol concentration measuring device based on grazing incidence method according to claim 1 is characterized in that: The shading sheet (7) is U-shaped.

4. The alcohol concentration measuring device based on grazing incidence method according to claim 1 is characterized in that: The optical signal receiving and processing unit comprises an optical filter (9), a charge coupler (10) and a computer; The optical filter (9) is mounted on a side of the charge coupler (10) facing the spectrometer, and the charge coupler (10) is electrically connected to the computer.

5. The alcohol concentration measuring device based on grazing incidence method according to claim 1 is characterized in that: The light source (1), the optical device, and the center of the beam splitter are coaxially arranged.

6. The alcohol concentration measuring device based on grazing incidence method according to any one of claims 1 to 5, characterized in that: The light source (1) is an LED light emitting diode.

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