Liquid refractive index measuring device based on Michelson interferometer

Abstract

The utility model discloses a liquid refractive index measuring device based on a Michelson interferometer, which relates to the technical field of refractive index measurement and comprises a base, a cross-shaped slide rail is fixedly connected above the base, a spectroscope is mounted at the center of the cross-shaped slide rail, and a positioning cylinder is slidably mounted on the cross-shaped slide rail. A laser transmitter, a beam expander, a reflective mirror, a cuvette and an observation screen are detachably mounted in the positioning cylinder, a plurality of positioning cores penetrate through the side wall of the positioning cylinder, and a concentric abutting cylinder capable of moving in the axial direction of the positioning cylinder is concentrically mounted on the outer side of the positioning cylinder. According to the device, the positioning cylinder is arranged, the inner side wall of the concentric abutting cylinder can abut against all the positioning cores at the same time, the laser transmitter, the beam expander, the reflective mirror, the cuvette or the observation screen are concentrically fixed to the positioning cylinder through the positioning cores, and at the moment, all instruments are correspondingly located on the same straight line; during refraction measurement, the respective positions do not need to be adjusted frequently, application is more convenient, and the measurement result is more accurate.

Description

Technical Field

[0001] The utility model relates to the technical field of refractive index measurement, in particular to a liquid refractive index measuring device based on a Michelson interferometer. Background Art

[0002] The liquid refractive index measuring device based on Michelson interferometer is an experimental method for measuring the refractive index of liquid. Michelson interferometer is an instrument that uses the interference principle of light to measure length or refractive index. It consists of a light source, a beam splitter, two reflectors and a detector. The light emitted by the light source is divided into two beams by the splitter, one of which returns after reaching a reflector along a straight path, and the other returns after passing through a sample and reflecting on another reflector. The two beams reunite at the splitter, and then the received light causes interference according to the optical path difference, and this interference phenomenon can be measured by the detector.

[0003] Among the existing patent documents, there is a patent with publication number CN 115791702 A and patent name "Liquid refractive index measurement device and drainage measurement method based on Michelson interferometer". This patent lacks concentric positioning devices for instruments such as helium-neon lasers, beam expanders, and reflectors. After these instruments are installed, especially after the beam expander is used to expand the light emitted by the helium-neon laser, it is even more impossible to ensure that the light passes through the reflector in a concentrated manner, resulting in the need to fine-tune each instrument after installation. This is not only time-consuming and labor-intensive, but also cannot guarantee the accuracy of the measurement.

[0004] Therefore, in view of the shortcomings of the above scheme in actual production and implementation, it has been revised and improved. At the same time, in the spirit and concept of seeking excellence, with the assistance of professional knowledge and experience, and after many ingenuity and experiments, the utility model was created, which provides a liquid refractive index measuring device based on Michelson interferometer to solve the above problems. Utility Model Content

[0005] The utility model provides a liquid refractive index measuring device based on a Michelson interferometer, which solves the problems in the prior art.

[0006] The technical solution of the utility model is achieved in this way:

[0007] The liquid refractive index measuring device based on Michelson interferometer comprises a base, a cross slide rail is fixedly connected to the top of the base, a beam splitter is installed at the center of the cross slide rail, a laser emitter, a beam expander, a reflector, a cuvette and an observation screen are respectively installed around the beam splitter, with the beam splitter as the center, the reflector is arranged at two places, one of which is located on the same straight line with the laser emitter and the beam expander, and the other is located on the same straight line with the cuvette and the observation screen; a positioning cylinder is slidably installed on the cross slide rail, the laser emitter, the beam expander, the reflector, the cuvette and the observation screen are all disassembled and fixed in the positioning cylinder, a plurality of positioning cores evenly distributed and facing the center of the positioning cylinder are connected through the side wall of the positioning cylinder, a concentric abutment cylinder capable of moving along the axial direction of the positioning cylinder is concentrically installed on the outer side of the positioning cylinder, the inner side wall of the concentric abutment cylinder can abut all the positioning cores at the same time, and the laser emitter, the beam expander, the reflector, the cuvette or the observation screen are respectively fixed concentrically with the positioning cylinder through the positioning core.

[0008] With this solution, a positioning tube is provided, and the inner wall of the concentric abutment tube is used to abut against all positioning cores at the same time. The laser emitter, beam expander, reflector, cuvette or observation screen are respectively fixed concentrically with the positioning tube through the positioning core. Since the heights of the positioning tubes are consistent, after the instruments are concentrically clamped in the positioning tubes, all the instruments are located on the same straight line. There is no need to frequently adjust their positions during refraction measurement, which is more convenient in application and the measurement results are more accurate.

[0009] As a preferred embodiment of the liquid refractive index measuring device based on Michelson interferometer, the concentric abutment cylinder and the positioning cylinder are assembled by threads, and the inner side wall of the concentric abutment cylinder is inclined.

[0010] By adopting this solution, in order to improve the flexibility of clamping, the inner wall of the concentric interference cylinder is tilted. When the positioning cylinder is rotated to move it axially, the concentric interference cylinder can push the positioning core to slide accordingly, thereby realizing the positioning of instruments of different sizes.

[0011] As a preferred embodiment of the liquid refractive index measuring device based on the Michelson interferometer, the outer side of the concentric abutment cylinder is also fixedly connected with a plurality of evenly distributed rotating handles.

[0012] With this solution, in order to facilitate the rotation of the concentric friction cylinder, a rotating handle is provided, which saves more effort when rotating the concentric friction cylinder.

[0013] As a preferred embodiment of the liquid refractive index measuring device based on Michelson interferometer, the end of the positioning core close to the concentric abutment cylinder is rounded.

[0014] By adopting this solution, in order to reduce the friction between the positioning core and the inner wall of the concentric friction cylinder, the end of the positioning core is set to a round head, so that the contact surface between the positioning core and the inner wall of the concentric friction cylinder will become smaller, and it will be more labor-saving when rotating the concentric friction cylinder.

[0015] As a preferred embodiment of the liquid refractive index measuring device based on the Michelson interferometer, a spring is also mounted on the core of the positioning core, and the spring can push the positioning core to slide toward the inner wall of the concentric abutment tube.

[0016] By adopting this solution, in order to facilitate the disassembly of each instrument, a spring is provided. When the positioning core is loosened, the positioning core can be pushed away from the instruments under the action of the spring, so that the disassembly of each instrument will be more convenient.

[0017] As a preferred embodiment of the liquid refractive index measuring device based on the Michelson interferometer, an L-shaped slide is fixedly connected to the bottom of the positioning cylinder, and the L-shaped slide is slidably connected to the cross slide rail.

[0018] With this solution, in order to facilitate the sliding of the positioning cylinder, an L-shaped sliding seat is provided for the sliding of the positioning cylinder, thereby facilitating the adjustment of its position.

[0019] As a preferred embodiment of the liquid refractive index measuring device based on the Michelson interferometer, the L-shaped slide seat is also equipped with a top screw, and the end of the top screw can contact the surface of the cross slide rail.

[0020] With this solution, in order to facilitate the positioning of the positioning tube, after each adjustment of the position of the positioning tube is completed, the positioning tube can be tightened by rotating the top screw.

[0021] As a preferred embodiment of the liquid refractive index measuring device based on Michelson interferometer, a liquid storage chamber is provided inside the cuvette, and the front and back of the liquid storage chamber are made of visible transparent glass and other materials. An injection port is provided through the top of the liquid storage chamber, and a plugging head is installed at the injection port, wherein the plugging head is installed by means of threads or the like.

[0022] With this solution, in order to facilitate the replacement of the liquid to be tested, a detachable plugging head is provided above the liquid storage cavity, thereby facilitating the replacement of the liquid to be tested.

[0023] As a preferred implementation of the liquid refractive index measuring device based on the Michelson interferometer, the reflector is limitedly clamped in the cavity at the rear side of the cuvette.

[0024] By adopting this solution, in order to reduce the number of installation steps, the reflector is directly clamped on the cuvette, and only the cuvette needs to be fixed during installation.

[0025] As a preferred embodiment of the liquid refractive index measuring device based on Michelson interferometer, the front and back of the observation screen are visualized, and it is made of visible transparent glass and other materials, and criss-crossing measurement grid lines are arranged on the front and back surfaces thereof.

[0026] With this solution, in order to facilitate the measurement of the refractive index, by setting the measurement grid lines, the refracted light source is spread on the observation screen. With the aid of the measurement grid lines and in conjunction with the measurement tools, the measurement grid lines are used as a reference during measurement, which makes it more convenient to measure data.

[0027] After adopting the above technical solution, the beneficial effects of the utility model are:

[0028] 1. By setting up the positioning tube and using the inner wall of the concentric contact tube to contact all the positioning cores at the same time, the laser emitter, beam expander, reflector, cuvette or observation screen are fixed concentrically with the positioning tube through the positioning core. Since the heights of the positioning tubes are consistent, after the instruments are concentrically clamped in the positioning tube, all the instruments are located on the same straight line. There is no need to frequently adjust their positions during refraction measurement, which is more convenient in application and the measurement results are more accurate.

[0029] 2. In order to improve the flexibility of clamping, the inner wall of the concentric interference cylinder is set at an angle. When the positioning cylinder is rotated to move it axially, the concentric interference cylinder can push the positioning core to slide accordingly, thereby realizing the positioning of instruments of different sizes.

[0030] 3. In order to reduce the friction between the positioning core and the inner wall of the concentric friction cylinder, the end of the positioning core is set to a round head, so that the contact area between the positioning core and the inner wall of the concentric friction cylinder will become smaller, and it will be more labor-saving when rotating the concentric friction cylinder.

[0031] 4. In order to facilitate the measurement of refractive index, the measurement grid lines are set, and the refracted light source is spread on the observation screen. With the assistance of the measurement grid lines and the measurement tools, the measurement grid lines are used as the reference during measurement, which will be more convenient when measuring data. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0033] Figure 1 The three-dimensional structure of the utility model Figure 1 ;

[0034] Figure 2 The three-dimensional structure of the utility model Figure 2 ;

[0035] Figure 3 for Figure 1 Schematic diagram of the refraction path of light in the figure;

[0036] Figure 4 for Figure 1 The three-dimensional structure diagram of the laser transmitter after installation in the positioning tube;

[0037] Figure 5 for Figure 1 The three-dimensional structure diagram of the middle beam expander after installation in the positioning tube;

[0038] Figure 6 for Figure 2 The three-dimensional structure diagram of the central reflector after installation in the positioning tube;

[0039] Figure 7 for Figure 1 A three-dimensional structural diagram of the middle cuvette after installation in the positioning cylinder;

[0040] Figure 8 for Figure 2 The three-dimensional structure diagram of the middle observation screen after installation in the positioning tube;

[0041] Fig. 9 for Figure 1 The three-dimensional structure of the central positioning tube Figure 1 ;

[0042] Fig.10 for Figure 1 The three-dimensional structure of the central positioning tube Figure 2 ;

[0043] Fig.11 for Fig. 9 Internal cross-sectional view in;

[0044] Fig.12 for Figure 7 The three-dimensional structure diagram of the cuvette in the middle;

[0045] Fig.13 for Fig.12 Internal cross-sectional view in;

[0046] Fig.14 for Figure 8 The three-dimensional structure diagram of the middle observation screen;

[0047] Fig.15 The laser passes through the colorimetric optical path which is not filled with the liquid to be tested;

[0048] Fig.16 The laser passes through the colorimetric optical path filled with the liquid to be tested;

[0049] In the figure: 1-base; 2-cross slide; 3-beam splitter; 4-laser emitter; 5-beam expander; 6-reflector; 7-cuvette; 8-observation screen; 9-positioning cylinder; 10-positioning core; 11-concentric abutment cylinder; 12-rotating handle; 13-spring; 14-L-shaped slide; 15-top screw; 16-liquid storage chamber; 17-sealing head; 18-measuring grid lines. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0051] like Figures 1 to 11 As shown, the liquid refractive index measuring device based on the Michelson interferometer comprises a base 1, a cross slide 2 is fixedly connected to the top of the base 1, a beam splitter 3 is installed at the center of the cross slide 2, and a laser emitter 4, a beam expander 5, a reflector 6, a cuvette 7 and an observation screen 8 are respectively installed around the beam splitter 3, and the reflector 6 is arranged at two locations, one of which is located on the same straight line as the laser emitter 4 and the beam expander 5, and the other is located on the same straight line as the cuvette 7 and the observation screen 8; a cross slide 2 is slidably arranged on the cross slide 2. A positioning cylinder 9 is installed, and the laser emitter 4, beam expander 5, reflector 6, cuvette 7 and observation screen 8 are all disassembled and fixed in the positioning cylinder 9. The side wall of the positioning cylinder 9 is penetrated and connected with multiple positioning cores 10 evenly distributed and facing the center of the circle. A concentric abutment cylinder 11 capable of moving along its axial direction is concentrically installed on the outer side of the positioning cylinder 9. The inner side wall of the concentric abutment cylinder 11 can abut all the positioning cores 10 at the same time, and the laser emitter 4, beam expander 5, reflector 6, cuvette 7 or observation screen 8 are respectively fixed concentrically with the positioning cylinder 9 through the positioning core 10.

[0052] like Fig.11 As shown, the concentric abutment cylinder 11 and the positioning cylinder 9 are assembled by threads, and the inner side wall of the concentric abutment cylinder 11 is inclined.

[0053] like Figure 10 to Figure 11 As shown, the outer side of the concentric abutment cylinder 11 is also fixedly connected with rotating handles 12 evenly distributed at four locations.

[0054] like Figures 9 to 11 As shown, the end of the positioning core 10 close to the concentric abutment tube 11 is a round end.

[0055] like Figures 9 to 11As shown, a spring 13 is also mounted on the core of the positioning core 10 , and the spring 13 can push the positioning core 10 to slide toward the inner wall of the concentric abutment cylinder 11 .

[0056] like Figures 9 to 11 As shown, the bottom of the positioning cylinder 9 is fixedly connected with an L-shaped slide 14, and the L-shaped slide 14 is slidably connected to the cross slide 2. The L-shaped slide 14 is also equipped with a top screw 15, and the end of the top screw 15 can contact the surface of the cross slide 2.

[0057] like Figure 12 to Figure 13 As shown, a liquid storage chamber 16 is provided inside the cuvette 7, and the front and rear of the liquid storage chamber 16 are both visible transparent glass, and an injection port is provided through the top of the liquid storage chamber 16, and a plugging head 17 is installed at the injection port, wherein the plugging head 17 is installed in a threaded manner. The reflector 6 is limitedly clamped in the cavity at the rear side of the cuvette 7.

[0058] like Fig.14 As shown, the viewing screen 8 is visible from front to back, is a visible transparent glass, and has crisscrossed measurement grid lines 18 arranged on the surfaces of the front and back sides thereof.

[0059] The working principle of this utility model:

[0060] When in use, the required measuring instruments, laser emitter 4 , beam expander 5 , reflector 6 , cuvette 7 and observation screen 8 are installed in the positioning tube 9 respectively.

[0061] During installation, the laser emitter 4, beam expander 5, reflector 6, cuvette 7 or observation screen 8 are placed at the center of the positioning tube 9, and the rotating handle 12 is turned to drive the concentric contact tube 11 to rotate and move. The inner wall of the concentric contact tube 11 can simultaneously contact all the positioning cores 10, and the laser emitter 4, beam expander 5, reflector 6, cuvette 7 or observation screen 8 are respectively fixed concentrically to the positioning tube 9 through the positioning core 10. Since the heights of the positioning tubes 9 are consistent, after the instruments are concentrically clamped in the positioning tube 9, all the instruments are correspondingly located on the same straight line. There is no need to frequently adjust their positions during refraction measurement, which is more convenient in application and the measurement results are more accurate.

[0062] During measurement, the laser is emitted by the laser emitter 4, expanded by the beam expander 5, and then split into two by the beam splitter 3 to form a parallel light beam and a vertical light beam. The parallel light beam is reflected by the reflector 6 and then refracted by the beam splitter 3 to the observation screen 8; at the same time, the vertical light beam passes through the liquid in the cuvette 7 to reach the reflector on the rear side thereof, and then reaches the beam splitter 3 after reflection, and reaches the observation screen 8 after transmission.

[0063] When calculating the refractive index of the liquid, the existing Michelson interferometer method is used for calculation, and the calculation method is as follows:

[0064] The Michelson interference fringes on the observation screen 8 can be clearly counted by naked eyes with the help of the measurement grid lines 18. Among them, the change number N1 of the interference fringes can represent the change of the optical path of the transmitted light (the liquid to be measured and the cuvette both contribute to the change of the optical path); in addition, considering the influence of the wall of the cuvette on the optical path, the cuvette is emptied and the change number N2 of the interference fringes is measured under the same conditions. According to the principle of geometric optics, Fig.15 (Light path of laser light passing through an empty cuvette) and Fig.16 (The optical path of the laser when it passes through a full load of the sample to be tested) can be seen.

[0065] In both cases, the angle between the light in the cuvette and the wall is always θ. Therefore, no matter what liquid the cuvette carries, the optical path difference caused by the wall is always the same (the paths of the light in the front and rear walls of the cuvette are always parallel, and the same rotation angle in both cases creates the same incident path in the front wall). It is only necessary to measure the number of fringe changes N1 and N2 when the pointer rotates through the same angle in both cases. In this way, ΔN = N1-N2, which eliminates the influence of the cuvette on the optical path of the transmitted light and only represents the optical path difference caused by the liquid in the cuvette. The refractive index of the liquid can be calculated through ΔN.

[0066] The formula for calculating the refractive index of a liquid is:

[0067]

[0068] In formula (1), ΔN=N1-N2, λ0 is the laser wavelength, t is the length from the inner surface of the front wall of the colorimeter to the inner surface of the rear wall, that is, the colorimeter inner diameter, and θ is the incident angle of the light, that is, the angle at which the ruler end is rotated.

[0069] In fact, N1 represents the influence of the colorimetric blood and the liquid to be tested on the optical path, and N2 represents the influence of the air between the colorimetric blood and the colorimetric blood on the optical path. According to the calculation formula of the optical path d = nd0 (where d0 is the path length of the light), it can be known that the refractive index and the path of the transmitted light will affect the optical path. Obviously, after rotating at a certain angle θ, d0 has changed. To accurately calculate the influence of the liquid to be tested on the optical path difference, the optical path difference caused by the air during the rotation of the colorimetric blood under the "no-load" condition must be eliminated.

[0070] like Fig.15 , the angle at which the light is incident on the air is θ2 = θ. In this way, the air in the container can be regarded as a "glass" with a relative refractive index n of 1. Formula (1) is used to calculate the number of fringe movements N' caused by the change in the optical path after it rotates by an angle of θ. This number is added to ΔN as a correction to obtain ΔN' = ΔN + N'. So far, it can be said that ΔN' can more accurately characterize the refractive index of the liquid to be measured than ΔN.

[0071] N' calculation formula:

[0072]

[0073] The calculation formula of liquid refractive index after two corrections:

[0074]

[0075] At this point, the influence of the glass wall and air has been eliminated through two corrections, and the refractive index of the liquid to be measured can be calculated more accurately through AN.

[0076] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A liquid refractive index measuring device based on a Michelson interferometer, comprising a base (1), a cross slide (2) fixedly connected to the top of the base (1), a beam splitter (3) installed at the center of the cross slide (2), a laser emitter (4), a beam expander (5), a reflector (6), a cuvette (7) and an observation screen (8) respectively installed around the beam splitter (3), with the beam splitter (3) as the center, wherein the reflector (6) is arranged at two locations, wherein one reflector (6) is located on the same straight line as the laser emitter (4) and the beam expander (5), and the other reflector (6) is located on the same straight line as the cuvette (7) and the observation screen (8); Features: A positioning cylinder (9) is slidably mounted on the cross slide rail (2); the laser emitter (4), beam expander (5), reflector (6), cuvette (7) and observation screen (8) are all disassembled and fixed in the positioning cylinder (9); a plurality of positioning cores (10) evenly distributed and oriented toward the center of the circle of the positioning cylinder (9) are connected through the side wall of the positioning cylinder (9); a concentric abutment cylinder (11) capable of moving along its axial direction is concentrically mounted on the outer side of the positioning cylinder (9); the inner side wall of the concentric abutment cylinder (11) can abut against all the positioning cores (10) at the same time, and the laser emitter (4), beam expander (5), reflector (6), cuvette (7) or observation screen (8) are respectively concentrically fixed to the positioning cylinder (9) through the positioning core (10).

2. The liquid refractive index measuring device based on Michelson interferometer according to claim 1, characterized in that: The concentric abutment cylinder (11) and the positioning cylinder (9) are assembled via threads, and the inner side wall of the concentric abutment cylinder (11) is arranged inclined.

3. The liquid refractive index measuring device based on Michelson interferometer according to claim 2, characterized in that: The outer side of the concentric abutment cylinder (11) is also fixedly connected to a plurality of evenly distributed rotating handles (12).

4. The liquid refractive index measuring device based on Michelson interferometer according to claim 1, characterized in that: The end of the positioning core (10) close to the concentric abutment cylinder (11) is a round end.

5. The liquid refractive index measuring device based on Michelson interferometer according to claim 4, characterized in that: The core of the positioning core (10) is also sleeved with a spring (13), and the spring (13) can push the positioning core (10) to slide toward the inner wall of the concentric abutment cylinder (11).

6. The liquid refractive index measuring device based on Michelson interferometer according to claim 1, characterized in that: The bottom of the positioning cylinder (9) is fixedly connected to an L-shaped sliding seat (14), and the L-shaped sliding seat (14) is slidably connected to the cross slide rail (2).

7. The liquid refractive index measuring device based on Michelson interferometer according to claim 6, characterized in that: The L-shaped sliding seat (14) is also equipped with a top screw (15), and the end of the top screw (15) can contact the surface of the cross slide rail (2).

8. The liquid refractive index measuring device based on Michelson interferometer according to claim 1, characterized in that: A liquid storage chamber (16) is provided inside the cuvette (7), and both the inside and outside of the liquid storage chamber (16) are visible. An injection port is provided through the top of the liquid storage chamber (16), and a plugging head (17) is installed at the injection port.

9. The liquid refractive index measuring device based on Michelson interferometer according to claim 8, characterized in that: The reflector (6) is position-limitingly clamped in the cavity at the rear side of the cuvette (7).

10. The liquid refractive index measuring device based on Michelson interferometer according to any one of claims 1 to 9, characterized in that: The viewing screen (8) is visualized from front to back, and has crisscrossed measurement grid lines (18) arranged on the surfaces of the front and back sides thereof.

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