Refractive index measurement method and measurement device based on two prisms

Abstract

The present application relates to the field of physical measurement technology, and particularly to a refractive index measuring method and measuring device based on two three-prisms, which solves the problem of inaccurate reading and large measurement error in the prior art when directly reading the laser deflection angle. The measuring method comprises a laser source, a plane mirror, three-prism I and three-prism II of the same material, and the following steps: S1, initialization process; S2, coarse adjustment process; S3, fine adjustment process; S4, obtaining the minimum deflection angle of three-prism I and three-prism II, and calculating the refractive index of the three-prism through the minimum deflection angle. The beneficial effect is that the minimum deflection angle is converted into judging whether the two light rays are parallel by using two three-prisms and the angle relationship between the incident light ray and the outgoing light ray; when the two laser light rays are parallel, the incident angle of the laser on the three-prism incident surface can be directly obtained, and then the minimum deflection angle of the three-prism is obtained, and the refractive index of the three-prism is calculated through the minimum deflection angle.

Description

Technical Field

[0001] This invention relates to the field of physical measurement technology, and in particular to a method and apparatus for measuring refractive index based on two prisms. Background Technology

[0002] Currently, most experimental textbooks in Chinese universities use the spectrometer minimum deflection angle method to measure the refractive index of glass. When light passes through a prism, it is deflected at the two interfaces of the prism. The angle at which the outgoing ray is deflected relative to the incident ray is called the deflection angle. The magnitude of the deflection angle changes with the incident angle and has a minimum value. The minimum deflection angle only occurs when the outgoing and incident rays are symmetrical about the prism. By measuring the minimum deflection angle, the refractive index of the prism material can be determined.

[0003] CN216978823U discloses a prism refractive index measuring device. It includes: a first crossbar, a support, a second crossbar, a third crossbar, a light source, a prism, a worktable, a telescope, an L-shaped support, an angle sensor, a rotating shaft, a sleeve, a microcontroller, a display, and a power supply. The left ends of the first, second, and third crossbars are fixed to the support. The lower end of the sleeve is fixed to the upper right end of the first crossbar. Two-thirds of the rotating shaft is inserted into the sleeve. The angle sensor is fixed to the lower right end of the second crossbar. The lower end of the angle sensor's rotating shaft is welded to the upper end of the rotating shaft. The left end of the L-shaped support is welded to the side of the upper end of the rotating shaft. The telescope is fixed to the upper end of the L-shaped support. The worktable is fixed to the upper part of the third crossbar. The light source is fixed to the left end of the worktable. The prism is placed in the center of the worktable, and the centers of the prism and the telescope are on the same horizontal plane.

[0004] The refractive index measuring device described above can measure the refractive index of a prism with high accuracy. However, directly observing the laser with a telescope during the measurement process can easily lead to visual fatigue and significant damage to eyesight. Furthermore, directly reading the laser deflection angle can result in inaccurate readings, increasing measurement errors. Summary of the Invention

[0005] This invention proposes a method and device for measuring the refractive index based on two prisms, which solves the problem of inaccurate readings and large measurement errors that easily occur when directly reading the laser deflection angle in the prior art.

[0006] The technical solution of this invention is implemented as follows:

[0007] The refractive index measurement method based on two prisms interference includes a laser source, a plane mirror, and prisms I and II of the same material. The laser source, plane mirror, and prisms I and II are all located at the same height to ensure that the laser emitted from the laser source can illuminate the plane mirror, prisms I and II, thus ensuring the smooth progress of the prism refractive index measurement process. The method also includes the following steps:

[0008] S1, Initialization process: Turn on the laser source, make the laser generated by the laser source coincide with the incident surface of prism I and the incident surface of prism II, and make the plane mirror parallel to the exit surface of prism II. Record the initial position of the laser source.

[0009] S2, coarse adjustment process: Rotate the laser source to reflect and refract the laser light at the incident surface of prism I; rotate prism II and the plane mirror in opposite directions to the laser source, with the laser source rotating at half the angle of rotation of prism II and the plane mirror. The laser light reflected from the incident surface of prism I is refracted at the incident surface of prism II, and then reflected by the plane mirror. After reflection at the incident surface of prism I, the laser light reaches the incident surface of prism II. Since the laser source rotation angle is half the rotation angle of prism II, the incident angle of the laser light on prism I is equal to the incident angle of the laser light on prism II.

[0010] S3, fine-tuning process: adjust the rotation angles of the laser source, prism II, and plane mirror so that the laser emission direction of the prism I exit surface is parallel to the laser reflection direction of the plane mirror, and record the position of the laser source after rotation;

[0011] S4. Calculate the angle between the laser source's rotated position and its initial position to obtain the minimum deflection angles of prisms I and II. Then, calculate the refractive indices of prisms I and II using these minimum deflection angles. When the laser emission direction from the exit surface of prism I is parallel to the laser reflection direction of the plane mirror, the incident angle of the laser on prism I is equal to the exit angle of the laser on prism I. In this case, the minimum deflection angle of prism I can be calculated from the incident angle. The angle between the rotated position of the laser source and its initial position is the incident angle of the laser on prism I. Finally, the refractive index of prism I can be calculated using the minimum deflection angle.

[0012] In S2, a convex lens and a receiving screen are set in the laser emission direction of the exit surface of prism I and the laser reflection direction of the plane mirror. The convex lens and the receiving screen are arranged in parallel, and the distance between the convex lens and the receiving screen is equal to the focal length of the convex lens. After the laser emitted from the exit surface of prism I and the laser reflected from the plane mirror pass through the convex lens, two light spots are displayed on the receiving screen. The rotation angle of the laser source and prism II is adjusted so that the two light spots coincide.

[0013] In step S3, the convex lens is removed, and an interference component is installed in its place. When the laser beam interferes with the receiving screen after passing through the interference component, the laser emission direction from the exit surface of prism I is parallel to the laser reflection direction from the plane mirror. The interference component allows for determination of whether the two laser beams are perfectly parallel, improving measurement accuracy.

[0014] A measuring device for a refractive index measurement method based on two prisms includes a base, a fixed frame on the base, and a detachable prism I on the fixed frame; a first rotating frame and a second rotating frame are rotatably connected to the base, a laser source is mounted on the first rotating frame, a plane mirror is mounted on the second rotating frame, and a detachable prism II is mounted on the second rotating frame, with the exit surface of prism II arranged parallel to the plane mirror; the incident surface of prism I coincides with the rotation center of the first rotating frame.

[0015] The first rotating frame includes an integrally connected laser source support and a rotating connection. The rotating connection is rotatably connected to the base, and the laser source is mounted on the laser source support. The laser source is a laser that emits laser light, and the laser source support keeps the laser horizontal, thereby keeping the emitted laser light horizontal.

[0016] The rotating connection part is equipped with two opposing arc-shaped locking blocks. The base is a disc structure, and the arc-shaped locking blocks engage with the edge of the disc structure. Angle scale lines are provided on the edge of the disc structure. By observing the corresponding positions of the arc-shaped locking blocks and the angle scale lines, the initial position and the position after rotation of the laser source during the measurement process can be quickly determined, and the rotation angle of the laser source can be quickly obtained, which facilitates the calculation of the refractive index of the prism.

[0017] The rotating connection part is provided with a connection hole, which corresponds to the center position of the disk structure. A rotating shaft connected to the base passes through the connection hole. The first rotating frame rotates around the center of the connection hole, and the middle position of the incident surface of prism I coincides with the rotation center of the first rotating frame, so that the laser can always irradiate the incident surface of prism I after the laser source rotates, ensuring the smooth operation of the refractive index measurement.

[0018] The base is equipped with a support frame, and a second rotating frame is rotatably mounted on the support frame. The second rotating frame is an L-shaped plate. A plane mirror is positioned inside the vertical portion of the L-shaped plate, and a triangular prism II is placed on the horizontal portion of the L-shaped plate, with the exit surface of the triangular prism II parallel to the vertical portion of the L-shaped plate. The first rotating frame is located below the support frame, and the second rotating frame is located above the support frame to avoid interference between the first and second rotating frames. The plane mirror is connected to the vertical portion of the L-shaped plate to ensure its stability during the rotation of the second rotating frame.

[0019] The lower side of the L-shaped plate is provided with a mounting shaft II, which is rotatably connected to the support frame. The incident surface of the prism II coincides with the rotation center of the mounting shaft II. The rotation center of the mounting shaft II corresponds to the side of the incident surface of the prism II closest to the prism I, so that after the laser source and the prism II rotate, the laser reflected from the incident surface of the prism I can illuminate the incident surface of the prism II, ensuring the smooth progress of the refractive index measurement.

[0020] The rotating connection part is equipped with a mounting shaft I, on which a gear I is mounted, and a gear II is mounted on a mounting shaft II. Gear I and gear II mesh, and the transmission ratio between gear I and gear II is 1:2. When the laser source rotates, it can drive the second rotating frame to rotate through the meshing of gear I and gear II. The rotation angle of the laser source is half the rotation angle of prism II, thus ensuring that the incident angle of the laser on the incident surfaces of prism I and prism II remains equal, which facilitates subsequent calculations and simplifies the calculation process.

[0021] The beneficial effects of this invention are as follows: This invention adopts a new method for measuring refractive index. Although its core principle is still to find the minimum deviation angle, it achieves innovation in the measurement method: by using two prisms and the angular relationship between the incident and outgoing rays, finding the minimum deviation angle is transformed into determining whether the two rays are parallel; when the two laser rays are parallel, the incident angle of the laser on the incident surface of the prism can be directly obtained, and then the minimum deviation angle of the prism can be obtained, and the refractive index of the prism can be calculated from the minimum deviation angle.

[0022] To improve measurement accuracy, a convex lens or interferometer can be used during the measurement process to determine whether the two laser beams are perfectly parallel. A convex lens allows for initial adjustment of the beam parallelism, while an interferometer observes the interference phenomenon to ensure accurate parallelism. Furthermore, the measurement process eliminates the need for a telescope to observe and read the laser angle, avoiding visual fatigue and potential vision damage to the experimenter. Based on this, the angle between the incident ray and the prism plane is measured, and the refractive index of the prism can be calculated using a formula.

[0023] By meshing gear I on the first rotating frame and gear II on the second rotating frame, with a transmission ratio of 1:2 between gear I and gear II, the rotation directions of prism II and plane mirror are opposite to the rotation direction of the laser source. The rotation angle of the laser source is half the rotation angle of prism II and plane mirror. This structural arrangement makes the laser incident angle on the incident surface of prism I equal to the laser incident angle on the incident surface of prism II, simplifying the calculation process and improving measurement efficiency. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the initial state of a prism during refractive index measurement.

[0026] Figure 2 This is a schematic diagram of the adjustment process when measuring the refractive index of a prism.

[0027] Figure 3 This is a schematic diagram of the structure after adjustment during the measurement of the refractive index of the prism.

[0028] Figure 4 This is a schematic diagram for coarse adjustment using a convex lens.

[0029] Figure 5 A schematic diagram for fine-tuning using the interference component.

[0030] Figure 6 This is a diagram showing the relationship between the apex angle and the angle of refraction of a prism.

[0031] Figure 7 This is a schematic diagram of refraction using prism I and prism II.

[0032] Figure 8 This is a schematic diagram of a refractive index measuring device based on two prisms.

[0033] Figure 9 This is a front view of a refractive index measuring device based on two prisms.

[0034] Figure 10 This is a schematic diagram of the rotating frame I.

[0035] In the diagram: 1. Base; 2. First rotating frame; 3. Support frame; 4. Laser source; 5. Fixing frame; 6. Second rotating frame; 7. Prism I; 8. Prism II; 9. Convex lens; 10. Receiving screen; 21. Laser source support; 22. Rotating connection; 221. Arc-shaped locking block; 222. Mounting shaft I; 223. Connecting hole; 224. Gear I; 61. Plane mirror; 62. Mounting shaft II; 63. Gear II; 91. Reflector; 92. Plane lens. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1, a method for measuring the refractive index based on two prisms, includes a laser source 4, a plane mirror 61, and two prisms, I 7 and II 8, made of the same material, and further includes the following steps:

[0038] S1, Initialization process: Turn on laser source 4, aligning the laser emitted by laser source 4 with the incident surfaces of prism I 7 and prism II 8, and ensuring that plane mirror 61 is parallel to the exit surface of prism II 8. Record the initial position of laser source 4; Figure 1 As shown, the OA side of prism I7, the OC side of prism II8, and the laser coincide, and point O is the rotation center of prism II8. The rotation center of laser source 4 is located in the middle of the OA side.

[0039] S2, coarse adjustment process: Rotate laser source 4 to reflect and refract the laser light at the incident surface of prism I7; rotate prism II8 and plane mirror 61 in the opposite direction to the rotation of laser source 4, with the rotation angle of laser source 4 being half the rotation angle of prism II8 and plane mirror 61. The laser light, after being reflected at the incident surface of prism I7, is refracted at the incident surface of prism II8, and then reflected at plane mirror 61 after refraction by prism II8. Figure 2 As shown, the incident laser a rotates clockwise around a point in the middle of the incident surface OA, and the prism II 8 rotates counterclockwise around point O, with the rotation angle of the prism II 8 being twice the rotation angle of the incident laser a. Specifically, after being refracted by the prism I 7, the incident laser a exits from the exit surface OB of the prism I 7 to form the outgoing laser b. After being reflected by the prism I 7, the incident laser a forms the reflected laser c. The reflected laser c enters the prism II 8 from the incident surface OC. The angle between the reflected laser c and the incident surface OC is equal to the angle between the incident laser a and the incident surface OA. After being refracted by the prism II 8, the reflected laser c exits from the exit surface CD of the prism II 8 to form the outgoing laser d. After being reflected by the plane mirror 61, the outgoing laser d forms the reflected laser e.

[0040] The angles between the incident laser a and the incident surface OA, and between the refracted laser c and the incident surface OC, are both θ. The apex angles ∠AOB of prism I7 and ∠OCD of prism II8 are both α. Since prism I7 and prism II8 are made of the same material (i.e., they have the same refractive index), the angles between the emitted laser b and the emitted surface OB, and between the emitted laser d and the emitted surface CD, are both φ. Because plane mirror 61 is arranged parallel to the emitted surface CD, the reflected laser e and plane mirror 61... The angle between the incident laser a and the outgoing laser b is φ; the angle between the incident laser a and the outgoing laser b is ∠ab=α+θ+φ, and the angle between the reflected laser c and the outgoing laser d is ∠cd=α+θ+φ. The reflected laser c rotates counterclockwise by 2θ relative to the incident laser a, and the reflected laser e rotates clockwise by 2φ relative to the outgoing laser d. Therefore, the angle between the reflected laser e and the incident laser a is ∠ae=α+θ+φ+2(φ-θ). ∠ab=∠ae=α+θ+φ if and only if φ=θ. In this case, the outgoing laser b and the reflected laser e are parallel.

[0041] S3, fine-tuning process: Adjust the rotation angles of laser source 4, prism II 8, and plane mirror 61 so that the laser emission direction of the exit surface of prism I 7 is parallel to the laser reflection direction of plane mirror 61, and record the position of laser source 4 after rotation; Figure 3 As shown, when the emitted laser b is parallel to the reflected laser e, the angle between the incident laser a and the incident surface OA of prism I7 is equal to the angle between the emitted laser b and the exit surface OB of prism I7. Therefore, the minimum deflection angle δ of prism I7 can be derived. m Minimum deviation angle δ m =180°-α-2θ.

[0042] S4. Calculate the angle between the position of laser source 4 after rotation and its initial position to obtain the minimum deflection angle of prism I7 and prism II8. Calculate the refractive index of prism I7 and prism II8 using the minimum deflection angle δ. m The refractive index n of prism I7 can be calculated, where the formula for calculating the refractive index n is:

[0043]

[0044] By utilizing two prisms and the angular relationship between the incident and outgoing rays, the method transforms the search for the minimum deflection angle into a determination of whether the two rays are parallel. This avoids directly observing the laser deflection angle using a telescope, thus preventing visual fatigue and damage to the eyesight of the experimenters. Simultaneously, the minimum deflection angle of the prism can be calculated from the rotation angle of the laser source 4, and then the refractive index can be calculated from the minimum deflection angle. The reading is convenient, quick, and easy to operate.

[0045] Example 2, based on Example 1, uses a method for measuring the refractive index of two prisms, such as... Figure 4 As shown, in S2, a convex lens 9 and a receiving screen 10 are positioned in the laser emission direction of the prism I7 and the laser reflection direction of the plane mirror 61, respectively. The convex lens 9 and the receiving screen 10 are arranged parallel to each other, and the distance between them is equal to the focal length of the convex lens 9. After passing through the convex lens 9, the laser emitted from the prism I7 and the reflected laser from the plane mirror 61 display two light spots on the receiving screen 10. The rotation angles of the laser source 4 and the prism II8 are adjusted to make the two light spots coincide. When placing the convex lens 9, the laser emission direction is first probed by hand to find the approximate location of the laser emission, and then the convex lens 9 and the receiving screen 10 are moved to that position. When the laser emitted from the prism I7 and the reflected laser from the plane mirror 61 are parallel, the distance between the two laser beams is less than the diameter of the convex lens 9, ensuring that both laser beams can pass through the convex lens 9 simultaneously, which facilitates the detection of whether the two laser beams are parallel.

[0046] In addition, when placing the convex lens 9, it is not necessary to place the convex lens 9 completely perpendicular to the two parallel lasers. The specific reason is that when the two parallel lasers are not perpendicular to the convex lens 9, the overlap of the two light spots can still represent the two laser beams.

[0047] Furthermore, such as Figure 5 As shown, in step S3, the convex lens 9 is removed, and an interference component is installed at the position of the convex lens 9. When the laser passes through the interference component and produces an interference phenomenon on the receiving screen 10, the laser emission direction of the prism I7 and the laser reflection direction of the plane mirror 61 are parallel. Due to the error of human observation, it is impossible to determine whether the two light spots are completely overlapping when using the convex lens 9, that is, the two emitted lasers are nearly parallel at this time. After making the two light spots on the receiving screen 10 overlap, the convex lens 9 is removed and replaced with the reflector 91 and plane lens 92 used for interference. The distance and angle of the reflector 91 and plane lens 92 are adjusted to make an interference phenomenon appear on the receiving screen 10. At this time, the emitted laser b and the reflected laser e are completely parallel, improving the measurement accuracy and the accuracy of the refractive index measurement.

[0048] Example 3: Based on Example 1 or Example 2, when the size of ∠AOB of prism I7 is not equal to the size of ∠OCD of prism II8, prism I7 is first used as the prism to be measured, with the vertex angle of prism I7 being α and the vertex angle of prism II8 being β.

[0049] like Figure 6 As shown, the refractive index of the prism is n. According to the law of refraction, on the incident side of the prism:

[0050]

[0051] According to the law of refraction on the exit side of a prism:

[0052]

[0053] The angular relationship is: θ″=α-θ′

[0054] In conclusion:

[0055]

[0056] like Figure 7 As shown, the angle between the incident laser a and the outgoing laser b is ∠ab = α + θ1 + φ1, and the angle between the reflected laser c and the outgoing laser d is ∠cd = β + θ1 + γ1. The reflected laser c rotates counterclockwise by 2θ1 relative to the incident laser a, and the reflected laser e rotates clockwise by 2γ1 relative to the outgoing laser d. Therefore, the angle between the reflected laser e and the incident laser a is ∠ae = β + θ1 + γ1 + 2(γ1 - θ1). ∠ab = ∠ae if and only if the outgoing laser b is parallel to the reflected laser e, and in this case, α + φ1 = β + 3γ1 - 2θ1.

[0057] The angular relationship of prism I7 can be derived as follows:

[0058]

[0059] The angular relationship of prism II8 is:

[0060]

[0061] By interchanging prism I7 and prism II8, and using prism II8 as the prism being measured, we can still obtain: β + φ² = α + 3γ² - 2θ².

[0062] The angular relationship of prism II8 is:

[0063]

[0064] The angular relationship of prism I7 is:

[0065]

[0066] Where θ1 and θ2 are the rotation angles of laser source 4 during the two measurements, respectively, the refractive index of the prism can be obtained by combining the above relationships.

[0067] Example 4, based on Example 1 or Example 2, such as Figure 8As shown, a measuring device for a refractive index measurement method based on two prisms includes a base 1, a fixed frame 5 on the base 1, and a detachable prism I 7 on the fixed frame 5; a first rotating frame 2 and a second rotating frame 6 are rotatably connected to the base 1, a laser source 4 is provided on the first rotating frame 2, a plane mirror 61 is provided on the second rotating frame 6, and a detachable prism II 8 is provided on the second rotating frame 6, with the exit surface of the prism II 8 arranged parallel to the plane mirror 61; the incident surface of the prism I 7 coincides with the rotation center of the first rotating frame 2. The laser source 4 is a laser that can emit laser light. The laser, prism I7, prism II8, and plane mirror 61 are located at the same height. The laser light emitted by the laser can pass through prism I7, prism II8, and plane mirror 61 in sequence to ensure the smooth progress of the measurement process. During the measurement process, prism I7 is placed on the fixed frame 5, and prism II8 is placed on the second rotating frame 6. The first rotating frame 2 drives the laser source 4 to rotate around the middle position of the incident surface of prism I7, and the second rotating frame 6 drives prism II8 to rotate.

[0068] Furthermore, such as Figure 10 As shown, the first rotating frame 2 includes an integrally connected laser source support 21 and a rotating connection 22. The rotating connection 22 is rotatably connected to the base 1, and the laser source 4 is mounted on the laser source support 21. The laser is detachably connected to the laser source support 21, which provides support for the laser and ensures its stability during rotation. When the laser is damaged, it can be removed from the laser source support 21 for replacement, ensuring the smooth progress of the measurement process.

[0069] Furthermore, the rotating connection part 22 is provided with two oppositely arranged arc-shaped locking blocks 221. The base 1 is a disc structure, and the arc-shaped locking blocks 221 engage with the edge of the disc structure. Angle scale lines are provided on the edge of the disc structure. The rotation angle of the first rotating frame 2 can be quickly obtained by observing the position of the angle scale lines corresponding to the edge of the arc-shaped locking blocks 221, which facilitates the improvement of the measurement efficiency of refractive index.

[0070] Furthermore, the rotating connecting part 22 is provided with a connecting hole 223, which corresponds to the center position of the disc structure. A rotating shaft connected to the base 1 passes through the connecting hole 223. The rotating connecting part 22 can rotate around the rotating shaft, ensuring that the first rotating frame 2 rotates smoothly.

[0071] Example 5, based on Example 4, provides a measuring device for a refractive index measurement method using two prisms, such as... Figure 9As shown, a support frame 3 is provided on the base 1, and a second rotating frame 6 is rotatably mounted on the support frame 3. The second rotating frame 6 is an L-shaped plate, with a plane mirror 61 located inside the vertical part of the L-shaped plate, and a triangular prism II 8 placed on the horizontal part of the L-shaped plate. The exit surface of the triangular prism II 8 is parallel to the vertical part of the L-shaped plate. The support frame 3 separates the first rotating frame 2 and the second rotating frame 6, with the first rotating frame 2 located below the support frame 3 and the second rotating frame 6 located above the support frame 3, thus preventing interference between the first rotating frame 2 and the second rotating frame 6 during rotation. After the triangular prism II 8 is placed on the second rotating frame 6, the incident surface of the triangular prism II 8 coincides with the rotation center of the second rotating frame 6, and the exit surface of the triangular prism II 8 is parallel to the vertical part of the L-shaped plate. The plane mirror 61 is connected to the vertical part of the L-shaped plate, thereby ensuring the stability of the plane mirror 61 during the rotation of the second rotating frame 6.

[0072] Furthermore, the upper surface of the horizontal part of the L-shaped plate is provided with a cross mark, which coincides with the rotation center of the second rotating frame 6. When the prism II 8 is placed, the position can be quickly found through the cross mark, which facilitates the use of the measuring device.

[0073] Furthermore, a mounting shaft II 62 is provided on the lower side of the L-shaped plate. The mounting shaft II 62 is rotatably connected to the support frame 3, and the incident surface of the prism II 8 coincides with the rotation center of the mounting shaft II 62. The rotation center of the mounting shaft II 62 corresponds to the side of the incident surface of the prism II 8 closest to the prism I 7, so that after the laser source 4 and the prism II 8 rotate, the laser reflected from the incident surface of the prism I 7 can illuminate the incident surface of the prism II 8, ensuring the smooth progress of the refractive index measurement.

[0074] Furthermore, such as Figure 9 As shown, the rotating connection part 22 is equipped with a mounting shaft I 222, a gear I 224 is mounted on the mounting shaft I 222, and a gear II 63 is mounted on the mounting shaft II 62. Gear I 224 and gear II 63 mesh, and the transmission ratio between gear I 224 and gear II 63 is 1:2. When the laser source 4 rotates, it can drive the second rotating frame 6 to rotate through the meshing of gear I 224 and gear II 63. The rotation angle of the laser source 4 is half the rotation angle of the prism II 8, thus ensuring that the incident angle of the laser on the incident surfaces of prism I 7 and prism II 8 remains equal, which facilitates subsequent calculations and simplifies the calculation process.

[0075] The above description is only a preferred embodiment of the present invention and is 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 within the protection scope of the present invention.

Claims

1. A method for measuring the refractive index based on two prisms, characterized in that, Including a laser source (4), a plane mirror (61), and prisms I (7) and II (8) of the same material, the following steps are also included: S1, Initialization process: Turn on the laser source (4) so ​​that the laser generated by the laser source (4) coincides with the incident surface of prism I (7) and the incident surface of prism II (8), and the plane mirror (61) is parallel to the exit surface of prism II (8). Record the initial position of the laser source (4). S2, coarse adjustment process: rotate the laser source (4) so ​​that the laser is reflected and refracted on the incident surface of prism I (7); rotate prism II (8) and plane mirror (61) in the opposite direction to the rotation direction of the laser source (4). The rotation angle of the laser source (4) is half the rotation angle of prism II (8) and plane mirror (61). The laser reflected by the incident surface of prism I (7) is refracted on the incident surface of prism II (8). After being refracted by prism II (8), the laser is reflected on plane mirror (61). S3, fine-tuning process: adjust the rotation angles of the laser source (4), prism II (8) and plane mirror (61) so that the laser emission direction of the prism I (7) is parallel to the laser reflection direction of the plane mirror (61), and record the position of the laser source (4) after rotation. S4, calculate the angle between the position of the laser source (4) after rotation and the initial position, obtain the minimum deviation angle of prism I (7) and prism II (8), and calculate the refractive index of prism I (7) and prism II (8) through the minimum deviation angle of prism I (7) and prism II (8).

2. The refractive index measurement method based on two prisms according to claim 1, characterized in that, In S2, a convex lens (9) and a receiving screen (10) are set in the laser emission direction of the prism I (7) and the laser reflection direction of the plane mirror (61). The convex lens (9) and the receiving screen (10) are arranged in parallel, and the distance between the convex lens (9) and the receiving screen (10) is equal to the focal length of the convex lens (9). The laser emitted from the prism I (7) and the reflected laser from the plane mirror (61) are displayed as two light spots on the receiving screen (10) after passing through the convex lens (9). The rotation angle of the laser source (4) and the prism II (8) is adjusted so that the two light spots coincide.

3. The refractive index measurement method based on two prisms according to claim 2, characterized in that, In S3, the convex lens (9) is removed and an interference component is set at the position of the convex lens (9). When the laser passes through the interference component and produces an interference phenomenon on the receiving screen (10), the laser emission direction of the exit surface of the prism I (7) is parallel to the laser reflection direction of the plane mirror (61).

4. A measuring device used in the refractive index measurement method based on two prisms as described in any one of claims 1 to 3, characterized in that, Includes a base (1), a fixed frame (5) on the base (1), and a detachable prism I (7) on the fixed frame (5); a first rotating frame (2) and a second rotating frame (6) are rotatably connected to the base (1), a laser source (4) is provided on the first rotating frame (2), a plane mirror (61) is provided on the second rotating frame (6), and a detachable prism II (8) is provided on the second rotating frame (6), with the exit surface of the prism II (8) arranged parallel to the plane mirror (61); the incident surface of the prism I (7) coincides with the rotation center of the first rotating frame (2).

5. The measuring device used in the refractive index measurement method based on two prisms according to claim 4, characterized in that, The first rotating frame (2) includes an integrally connected laser source support (21) and a rotating connection (22). The rotating connection (22) is rotatably connected to the base (1), and the laser source (4) is mounted on the laser source support (21).

6. The measuring device used in the refractive index measurement method based on two prisms according to claim 5, characterized in that, The rotating connection part (22) is provided with two oppositely arranged arc-shaped locking blocks (221), the base (1) is a disc structure, and the arc-shaped locking blocks (221) are engaged with the edge of the disc structure; the edge of the disc structure is provided with angle scale lines.

7. The measuring device used in the refractive index measurement method based on two prisms according to claim 6, characterized in that, The rotating connection part (22) is provided with a connection hole (223), which corresponds to the center position of the disc structure. A rotating shaft connected to the base (1) is inserted through the connection hole (223).

8. The measuring device used in the refractive index measurement method based on two prisms according to any one of claims 5 to 7, characterized in that, A support frame (3) is provided on the base (1). The second rotating frame (6) is rotatably mounted on the support frame (3). The second rotating frame (6) is an L-shaped plate. The plane mirror (61) is located on the inner side of the vertical part of the L-shaped plate. The triangular prism II (8) is placed on the horizontal part of the L-shaped plate. The exit surface of the triangular prism II (8) is parallel to the vertical part of the L-shaped plate.

9. The measuring device used in the refractive index measurement method based on two prisms according to claim 8, characterized in that, The lower side of the L-shaped plate is provided with a mounting shaft II (62), which is rotatably connected to the support frame (3). The incident surface of the prism II (8) coincides with the rotation center of the mounting shaft II (62).

10. The measuring device used in the refractive index measurement method based on two prisms according to claim 9, characterized in that, The rotating connection part (22) is provided with a mounting shaft I (222), a gear I (224) is provided on the mounting shaft I (222), and a gear II (63) is provided on the mounting shaft II (62). The gear I (224) meshes with the gear II (63), and the transmission ratio of the gear I (224) and the gear II (63) is 1:2.

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