A non-contact alcohol concentration measuring device and method based on a ring-shaped light path

Abstract

The non-contact alcohol concentration measuring device based on the ring-shaped light path comprises a laser light source, a filter, a first right-angle prism, a second right-angle prism, a cuvette, a first mirror, a second mirror, a CCD and a computer, and the first right-angle prism, the cuvette, the second right-angle prism, the first mirror and the second mirror form a ring-shaped light path. When measuring, the laser beam output by the laser light source passes through the cuvette containing alcohol (to be measured) in the ring-shaped light path for multiple times, the position of the laser beam is loaded with the alcohol concentration information when the laser beam is emitted from the ring-shaped light path, finally, the CCD collects the laser spot position information and transmits it to the computer to establish the relationship curve of different known alcohol concentrations and laser spot positions, and the accurate concentration of the alcohol to be measured is determined. The present application has many advantages such as real-time detection, rapidity, safety and accuracy, is beneficial to the miniaturization of the equipment, and has a wide application prospect in the field of alcohol concentration measurement and other solution concentration measurement.

Description

Technical Field

[0001] This invention belongs to the field of alcohol concentration measurement, specifically relating to a non-contact alcohol concentration measurement device and method based on a ring optical path. Background Technology

[0002] Accurate measurement of alcohol solution concentration is crucial in many fields. In medical practice, it is key to assessing drug dosage and concentration. Doctors and pharmacists need to accurately determine the alcohol content in solutions to ensure patients receive the correct therapeutic dose and avoid side effects or poor treatment outcomes. In chemical research, accurate measurement of alcohol solution concentration is essential for preparing reactants, calculating reaction rates, and evaluating reaction results, helping researchers obtain reliable data and advancing scientific research. In industrial production, many industries (such as cosmetics, food, and beverage manufacturing) use alcohol solutions as raw materials or cleaning agents; accurate measurement of alcohol solution concentration ensures consistent product quality and compliance with relevant production standards.

[0003] In general, accurate measurement of alcohol concentration is of great significance for medical, chemical research, and industrial production. It helps ensure patient safety, achieve scientific progress, and guarantee product quality; therefore, accurate measurement of alcohol concentration is crucial. Different concentrations of alcohol have different refractive indices, and the concentration of the alcohol to be measured can be obtained by measuring the refractive index. Currently, commonly used methods for measuring the refractive index of alcohol mainly include the following:

[0004] (1) Laser irradiation method: A method for measuring refractive index based on the reflection of the liquid layer on the glass plate and the refraction of the liquid.

[0005] (2) Diffraction grating method: The diffraction grating method is a method of measuring the refractive index of a liquid using a cubic glass sample cell, a diffraction grating and a laser.

[0006] (3) Fiber Young's Interference Method: The fiber Young's interference method uses optical fiber as a coherent light source to achieve Young's interference, obtain a wide and bright interference pattern, and then obtain the refractive index of the liquid by measuring the fringe width.

[0007] (4) Grazing incidence method: The grazing incidence method is based on the principle of total internal reflection. It calculates the refractive index of the liquid to be tested by measuring the exit angle of the light rays at the critical angle.

[0008] All the methods described above utilize a specific wavelength of laser light incident on the liquid being tested. Since the physical optical processes of reflection, refraction, diffraction, and interference of light by the liquid are related to its refractive index, a change in the refractive index alters the effect of these processes on the light path. The refractive index of the liquid can be calculated by testing and characterizing this variable. However, all of these methods suffer from a limited propagation distance of the light beam within the liquid. Therefore, when the change in the liquid's refractive index is small, test accuracy is difficult to guarantee; increasing the propagation distance can only be achieved by enlarging the container, which is not conducive to equipment miniaturization or testing small quantities of liquid. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a non-contact alcohol concentration measuring device and method based on a ring optical path, which has many advantages such as real-time detection, speed, safety and accuracy, in order to overcome the shortcomings of the prior art.

[0010] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a non-contact alcohol concentration measuring device based on a ring optical path. The measuring device includes a laser source, a filter, a first right-angle prism, a second right-angle prism, a cuvette, a first reflector, a second reflector, a CCD, and a computer. The first right-angle prism, cuvette, second right-angle prism, first reflector, and second reflector form a ring optical path. One cycle of the laser beam output by the laser source along the complete optical path is as follows: the laser beam output by the laser source passes through the filter and is horizontally incident on the cuvette containing alcohol; the laser beam passes horizontally through the cuvette and is horizontally incident on the second right-angle prism and deflected by 90°; the laser beam exits the second right-angle prism and is horizontally incident on the first reflector and deflected by 90°; the laser beam exits the first reflector and is horizontally incident on the second reflector and... After being deflected by 90°, the laser beam exits the second reflecting mirror and is horizontally incident on the first right-angle prism. It is then deflected again by 90° and exits the first right-angle prism before being horizontally incident on the cuvette once more. After each cycle, the laser beam output from the laser source shifts downwards by a certain distance before starting the next cycle. After multiple cycles, the laser beam is horizontally incident on the CCD from below the second right-angle prism. The CCD collects the laser spot position information and transmits it to the computer. The computer then uses fitting to determine the laser spot position corresponding to the concentration of alcohol contained in the cuvette. The computer establishes relationship curves between different known alcohol concentrations and laser spot positions. An unknown concentration of alcohol is then placed in the cuvette and measured using the measuring device. The measured laser spot position is substituted into the established relationship curve to obtain the concentration of the alcohol to be tested.

[0011] In this invention's non-contact alcohol concentration measuring device, a first right-angle prism, a cuvette, a second right-angle prism, a first reflector, and a second reflector form a ring optical path. During measurement, the laser beam output from the laser source passes through the cuvette containing the alcohol to be measured multiple times within the ring optical path. When the laser beam exits the ring optical path, its position carries the alcohol concentration information. Finally, a CCD collects the laser spot position information and transmits it to a computer. The computer then establishes relationship curves between different known alcohol concentrations and the laser spot position, and determines the precise concentration of the alcohol to be measured. Precise measurement of alcohol concentration can be achieved by controlling the number of times the same laser beam passes through the cuvette. This invention offers numerous advantages, including real-time detection, speed, safety, and accuracy, and facilitates device miniaturization. It has broad application prospects in alcohol concentration measurement and other solution concentration measurement fields.

[0012] Preferably, the laser light source is fixed on the first frame, the first right-angle prism is fixed on the second frame, the second right-angle prism is fixed on the third frame, the first reflector is fixed on the fourth frame, the second reflector is fixed on the fifth frame, the elevation angles of the first, second, third, fourth, and fifth frames are adjustable, and the cuvette is fixed on the dry plate holder.

[0013] Preferably, the third lens frame has a light-transmitting hole located below the second right-angle prism. After multiple cycles, the laser beam passes through the light-transmitting hole and is horizontally incident on the CCD.

[0014] Preferably, the laser light source has a center wavelength of 520±5nm, an optical power of 5mW, and a spot size of 3.5mm.

[0015] Preferably, the filter is a circular gradient filter with a working wavelength of 240–1200 nm and an optical density OD value of 0.04–2.0.

[0016] Preferably, the operating wavelengths of the first reflector and the second reflector are 250–600 nm, respectively.

[0017] Preferably, the CCD has a resolution of 1292×964, a photosensitive surface of 1 / 3 inch, and a pixel size of 3.75×3.75μm.

[0018] A non-contact alcohol concentration measurement method implemented by the above-mentioned non-contact alcohol concentration measurement device based on a ring optical path includes the following steps:

[0019] (1) Prepare multiple groups of alcohol solutions with different concentrations using deionized water and anhydrous ethanol for later use;

[0020] (2) Take an appropriate amount of alcohol solution from a set of prepared alcohol solutions, put it into a cuvette, turn on the laser light source, and adjust the positions of the laser light source, the first right-angle prism, the second right-angle prism, the first reflector, and the second reflector. The measuring device works, and after several cycles, the laser beam is horizontally incident on the CCD from below the second right-angle prism. The CCD collects the laser spot position information and transmits it to the computer. The computer fits and determines the laser spot position corresponding to the concentration of alcohol in the cuvette, thus obtaining a laser spot position corresponding to a known alcohol concentration.

[0021] (3) For other groups of alcohol solutions, repeat step (2) to obtain the laser spot positions corresponding to different known alcohol concentrations. The computer then establishes different relationship curves between known alcohol concentrations and laser spot positions.

[0022] (4) The unknown concentration of the alcohol to be tested is placed into a cuvette and measured by the measuring device. The computer substitutes the measured laser spot position into the established relationship curve to obtain the concentration of the alcohol to be tested.

[0023] Preferably, the computer determines the laser spot position using Gaussian fitting according to the following formula:

[0024] I(x)=I0exp[-(x-x0) 2 / s 2 ]

[0025] Where I0 is the relative light intensity at the center of the laser spot; s is the laser spot radius, and the position where the light intensity drops to 1 / e of the center is taken as the edge of the spot to obtain the laser spot radius s; x0 is the center position of the laser spot. After obtaining the Gaussian fitting curve, the coordinate x corresponding to the maximum value of the light intensity I(x) on the Gaussian fitting curve is taken as the center position of the laser spot.

[0026] Compared with existing technologies, this invention has the following advantages: This invention utilizes the different refractive indices of alcohol solutions of varying concentrations to achieve non-contact measurement of alcohol concentration based on a ring optical path. During measurement, firstly, different laser spot positions corresponding to different known alcohol concentrations are measured (different laser spot positions correspond to different refractive indices). By fitting a large amount of data, a relationship curve between different known alcohol concentrations and laser spot positions is obtained. Then, the precise concentration of the alcohol to be measured is accurately measured and determined. This invention has many advantages such as real-time detection, speed, safety, and accuracy, and facilitates equipment miniaturization. It has broad application prospects in alcohol concentration measurement and other solution concentration measurement fields. Attached Figure Description

[0027] Figure 1 This is a schematic block diagram showing the connections of the various components of the non-contact alcohol concentration measuring device in Example 1;

[0028] Figure 2 This is a schematic diagram showing the structural connections of the components of the non-contact alcohol concentration measuring device in Example 1;

[0029] Figure 3 This is a diagram showing the effect of installing the first right-angle prism on the second frame in Example 1.

[0030] Figure 4 This is a diagram showing the effect of installing the second right-angle prism on the third frame in Example 1.

[0031] Figure 5 This is a front view of the cuvette in Example 1;

[0032] Figure 6 These are the relationship curves between different known alcohol concentrations and laser spot positions established in Example 2;

[0033] The specific reference numerals in the figure are as follows:

[0034] 1-Laser source, 11-First frame, 2-Filter, 3-First right-angle prism, 31-Second frame, 4-Second right-angle prism, 41-Third frame, 42-Light aperture, 5-Cuvette, 51-Dry plate holder, 6-First reflecting mirror, 61-Fourth frame, 7-Second reflecting mirror, 71-Fifth frame, 8-CCD, 9-Computer, 10-Laser beam. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified, structures and components not limited in this invention utilize existing technology.

[0036] Example 1: A non-contact alcohol concentration measuring device based on a ring optical path, such as Figures 1-5As shown, it includes a laser light source 1, a filter 2, a first right-angle prism 3, a second right-angle prism 4, a cuvette 5, a first reflecting mirror 6, a second reflecting mirror 7, and a CCD. 8 and computer 9, the first right-angle prism 3, cuvette 5, second right-angle prism 4, first reflector 6, and second reflector 7 form a ring optical path. The laser source 1 is fixed on the first frame 11, the first right-angle prism 3 is fixed on the second frame 31, the second right-angle prism 4 is fixed on the third frame 41, the first reflector 6 is fixed on the fourth frame 61, and the second reflector 7 is fixed on the fifth frame 71. The elevation angles of the first frame 11, second frame 31, third frame 41, fourth frame 61, and fifth frame 71 are adjustable. The cuvette 5 is fixed on the dry plate holder 51. A light-transmitting hole 42 is opened on the third frame 41, located below the second right-angle prism 4. One cycle of the laser beam 10 output by the laser source 1 along the complete optical path is as follows: the laser beam 10 output by the laser source 1 passes through the filter 2 and then... The laser beam 10 passes horizontally above (but does not pass through) the first right-angle prism 3 and enters the cuvette 5 containing alcohol. After passing horizontally through the cuvette 5, the laser beam 10 enters the second right-angle prism 4 and deflects by 90°. After exiting the second right-angle prism 4, the laser beam 10 enters the first reflecting mirror 6 and deflects by 90°. After exiting the first reflecting mirror 6, the laser beam 10 enters the second reflecting mirror 7 and deflects by 90°. After exiting the second reflecting mirror 7, the laser beam 10 enters the first right-angle prism 3 and deflects by 90°. After exiting the first right-angle prism 3, the laser beam 10 enters the cuvette 5 horizontally again. After each cycle, the laser beam 10 output from the laser source 1 shifts downwards by a certain distance and begins the next cycle. After several cycles, the laser beam 10 enters the CCD horizontally through the light-transmitting aperture 42 below the second right-angle prism 4. 8. The CCD 8 collects the laser spot position information and transmits it to the computer 9. The computer 9 uses fitting to determine the laser spot position corresponding to the concentration of alcohol contained in the cuvette 5. The computer 9 establishes a relationship curve between different known alcohol concentrations and laser spot positions. The alcohol of unknown concentration is placed into the cuvette 5 and measured by the measuring device. The measured laser spot position is substituted into the established relationship curve to obtain the concentration of the alcohol to be tested.

[0037] In Example 1, the center wavelength of laser source 1 is 520±5nm, the optical power is 5mW, and the spot size is 3.5mm. Figures 1-5The multiple laser beams 10 shown are only used to schematically represent the direction of several cycles of laser beams simultaneously, not the direction of a single laser beam in a single cycle; the filter 2 is a circular gradient filter 2 with a diameter of 50 mm, a thickness of 2 mm, a working wavelength of 240–1200 nm, and an optical density OD value of 0.04–2.0; the first right-angle prism 3 and the second right-angle prism 4 both have a hypotenuse length of 35.4 mm, a right-angle side length of 25.0 mm, and a height of 25.0 mm; the first reflector 6 and the second reflector 7 both have a diameter of 50.8 mm, a thickness of 12.7 mm, and a working wavelength of 250–600 nm; the CCD 8 has a resolution of 1292 × 964, a photosensitive surface of 1 / 3 inch, and a pixel size of 3.75 × 3.75 μm.

[0038] Example 2: A non-contact alcohol concentration measurement method implemented using the non-contact alcohol concentration measurement device based on a ring optical path according to Example 1, comprising the following steps:

[0039] (1) Prepare 21 groups of alcohol solutions with different concentrations using deionized water and anhydrous ethanol. The concentration range is 0% to 100%, and the concentration interval is 5%. That is, the concentrations of the 21 groups of alcohol solutions are 0%, 5%, 10%, 15%, ..., 95%, and 100%, respectively. The volume of each group of alcohol solutions is not less than 50 mL.

[0040] (2) Take an appropriate amount of alcohol solution from a set of prepared alcohol solutions and put it into cuvette 5. Turn on laser source 1. After adjusting the positions of laser source 1, first right-angle prism 3, second right-angle prism 4, first reflector 6, and second reflector 7, the measuring device works. After several cycles, laser beam 10 is horizontally incident on CCD 8 from below second right-angle prism 4. CCD 8 collects laser spot position information and transmits it to computer 9. Computer 9 displays the relative position of laser spot in the vertical direction in CCD 8. Computer 9 fits and determines the laser spot position corresponding to the concentration of alcohol in cuvette 5, that is, obtains a laser spot position corresponding to a known alcohol concentration.

[0041] Computer 9 determines the laser spot position using Gaussian fitting according to the following formula:

[0042] I(x)=I0exp[-(x-x0) 2 / s 2 ]

[0043] Where I0 is the relative light intensity at the center of the laser spot; s is the laser spot radius, which is obtained by taking the position where the light intensity drops to 1 / e of the center as the edge of the spot; x0 is the center position of the laser spot, which is obtained by taking the coordinate x corresponding to the maximum value of light intensity I(x) on the Gaussian fitting curve as the center position of the laser spot.

[0044] (3) For other groups of alcohol solutions, repeat step (2) to obtain the laser spot positions corresponding to different known alcohol concentrations. Based on this, computer 9 establishes different relationship curves between known alcohol concentrations and laser spot positions, such as... Figure 6 As shown, the horizontal axis represents the relative position of the vertical laser spot in CCD 8, and the vertical axis represents the alcohol concentration.

[0045] (4) The unknown concentration of the alcohol to be tested is placed into the cuvette 5 and measured by the measuring device. The computer 9 substitutes the measured laser spot position into the established relationship curve to obtain the concentration of the alcohol to be tested.

Claims

1. A non-contact alcohol concentration measuring device based on a ring optical path, characterized in that, The measuring device includes a laser source, a filter, a first right-angle prism, a second right-angle prism, a cuvette, a first reflector, a second reflector, a CCD, and a computer. The first right-angle prism, cuvette, second right-angle prism, first reflector, and second reflector form a ring optical path. One cycle of the laser beam output from the laser source along the complete optical path is as follows: the laser beam passes through the filter and is horizontally incident on the cuvette containing alcohol; the laser beam passes horizontally through the cuvette and is horizontally incident on the second right-angle prism and deflected by 90°; the laser beam exits the second right-angle prism and is horizontally incident on the first reflector and deflected by 90°; the laser beam exits the first reflector and is horizontally incident on the second reflector and deflected by 90°; the laser beam exits the second reflector and is horizontally incident on the water... The laser beam is incident horizontally on the first right-angle prism and deflected by 90°. After exiting the first right-angle prism, the laser beam is incident horizontally on the cuvette again. After each cycle, the laser beam output by the laser source shifts downward a certain distance and begins the next cycle. After multiple cycles, the laser beam is incident horizontally on the CCD from below the second right-angle prism. The CCD collects the laser spot position information and transmits it to the computer. The computer fits and determines the laser spot position corresponding to the concentration of alcohol contained in the cuvette. The computer establishes relationship curves between different known alcohol concentrations and laser spot positions. The alcohol of unknown concentration is placed in the cuvette and measured by the measuring device. The measured laser spot position is substituted into the established relationship curve to obtain the concentration of the alcohol to be tested.

2. The non-contact alcohol concentration measuring device based on a ring optical path according to claim 1, characterized in that, The laser light source is fixed on the first frame, the first right-angle prism is fixed on the second frame, the second right-angle prism is fixed on the third frame, the first reflector is fixed on the fourth frame, the second reflector is fixed on the fifth frame, and the tilt angles of the first, second, third, fourth, and fifth frames are adjustable. The cuvette is fixed on the dry plate holder.

3. The non-contact alcohol concentration measuring device based on a ring optical path according to claim 2, characterized in that, The third lens frame has a light-transmitting hole located below the second right-angle prism. After multiple cycles, the laser beam passes through the light-transmitting hole and is horizontally incident on the CCD.

4. The non-contact alcohol concentration measuring device based on a ring optical path according to claim 1, characterized in that, The laser source has a center wavelength of 520±5 nm, an optical power of 5 mW, and a spot size of 3.5 mm.

5. The non-contact alcohol concentration measuring device based on a ring optical path according to claim 1, characterized in that, The filter is a circular gradient filter with a working wavelength of 240~1200 nm and an optical density OD value of 0.04~2.

0.

6. The non-contact alcohol concentration measuring device based on a ring optical path according to claim 1, characterized in that, The operating wavelengths of the first and second reflectors are 250~600 nm, respectively.

7. The non-contact alcohol concentration measuring device based on a ring optical path according to claim 1, characterized in that, The CCD has a resolution of 1292×964, a photosensitive surface of 1 / 3 inch, and a pixel size of 3.75×3.75 μm.

8. A non-contact alcohol concentration measurement method using any one of the non-contact alcohol concentration measuring devices based on a ring optical path according to claims 1 to 7, characterized in that, Includes the following steps: (1) Prepare multiple alcohol solutions of different concentrations using deionized water and anhydrous ethanol for later use; (2) Take an appropriate amount of alcohol solution from a set of prepared alcohol solutions, put it into a cuvette, turn on the laser source, and adjust the positions of the laser source, the first right-angle prism, the second right-angle prism, the first reflector, and the second reflector. The measuring device will work. After several cycles, the laser beam will be horizontally incident on the CCD from below the second right-angle prism. The CCD will collect the laser spot position information and transmit it to the computer. The computer will fit and determine the laser spot position corresponding to the concentration of alcohol in the cuvette, thus obtaining a laser spot position corresponding to a known alcohol concentration. (3) For other groups of alcohol solutions, repeat step (2) to obtain the laser spot positions corresponding to different known alcohol concentrations. The computer then establishes different relationship curves between known alcohol concentrations and laser spot positions. (4) The unknown concentration of the alcohol to be tested is placed into a cuvette and measured by the measuring device. The computer substitutes the measured laser spot position into the established relationship curve to obtain the concentration of the alcohol to be tested.

9. The non-contact alcohol concentration measurement method according to claim 8, characterized in that, The computer determines the laser spot position using Gaussian fitting according to the following formula: ,in, The relative light intensity at the center of the laser spot is denoted as s; the laser spot radius is obtained by taking the position where the light intensity drops to 1 / e of the center as the edge of the spot. After obtaining the Gaussian fitting curve at the center position of the laser spot, the light intensity on the Gaussian fitting curve is... The coordinate x corresponding to the maximum value is taken as the center position of the laser spot.

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