Device and method for measuring prism refractive index based on mobile phone APP

Abstract

The present invention provides a device and method for measuring the refractive index of a prism based on a mobile phone APP. The measuring device includes: a laser source, a rotating platform and an angle measuring fixture; the laser source is used to output laser light; the rotating platform is used to adjust the direction of the prism to be measured relative to the laser light; the angle measuring fixture is used to measure the first light direction of the laser before it is refracted by the prism and the second light direction after it is refracted by the prism using a mobile phone. The measuring device of the present invention has a simple structure and is easy to manufacture, which greatly saves costs. In the actual angle measurement process, the two functions of angle measurement and refractive index calculation are realized based on the mobile phone APP using the gyroscope sensor and accelerometer of the mobile phone, eliminating the link of manual calculation, and the measurement method is simple and fast.

Description

Technical Field

[0001] The present invention relates to the field of refractive index measurement technology, and in particular to a device and method for measuring the refractive index of a prism based on a mobile phone APP. Background Art

[0002] At present, in the experimental teaching of measuring the refractive index of a prism, a spectrometer is generally used to measure the minimum deflection angle and the prism angle of the light after two refractions of the prism. However, the structure of the spectrometer is relatively complex and the cost is relatively high. In addition, in the process of measuring the angle, the adjustment of the spectrometer is very cumbersome and complicated (refer to "Zhang Yanan, Xu Fei, Chen Yulin. Adjustment method of measuring the vertex angle of a prism using a spectrometer [J]. Experimental Science and Technology, 2008 (03): 33-34 + 97."), and it is not easy to operate.

[0003] With the rapid development of society, smart phones have entered people's daily lives and become an indispensable item for people. Generally, smart phones are equipped with a variety of sensors such as force, heat, sound, electricity, magnetism, and GPS positioning systems, and can download corresponding application software. Through these application software, various physical quantities can be measured: such as time, length, angle, slope, distance, height, area, pressure, sound intensity level, magnetic induction intensity, etc. Therefore, in this context, how to provide a measurement device and method for measuring the refractive index of a prism based on a mobile phone, which can save the cost of experimental equipment on the one hand, and make the experimental process more convenient and easy to operate on the other hand, is a problem that needs to be solved at present. Summary of the invention

[0004] In order to solve the problems that the spectrometer used in the existing prism refractive index measurement experiment has a complex structure and the spectrometer adjustment is cumbersome when measuring the angle, the present invention provides a prism refractive index measurement device and method based on a mobile phone APP.

[0005] On the one hand, the present invention provides a prism refractive index measuring device based on a mobile phone APP, comprising: a laser source, a rotating platform and an angle measuring fixture;

[0006] The laser source is used to output laser light;

[0007] The rotating platform is used to adjust the direction of the prism to be tested relative to the laser;

[0008] The angle measuring fixture is used to measure the first light direction of the laser before it is refracted by the prism and the second light direction of the laser after it is refracted by the prism using a mobile phone.

[0009] Furthermore, the rotating platform includes a base plate, a support shaft fixed on the base plate, and a turntable rotatable along the support shaft, and the turntable is provided with a groove for fixing the prism.

[0010] Furthermore, a through hole is provided on the support shaft, and a two-section frustum is provided in the middle of the turntable, and the small-diameter end of the two-section frustum matches the through hole.

[0011] Furthermore, the groove is a triangular groove arranged in the middle of the turntable.

[0012] Furthermore, the angle measuring fixture includes a clamping portion for fixing the mobile phone, a supporting portion located above the clamping portion, and a cross-shaped protrusion arranged on the supporting portion, wherein the cross-shaped protrusion is provided with a collimating slit, and the clamping portion, the supporting portion and the cross-shaped protrusion are integrally formed.

[0013] Furthermore, the clamping portion includes a first clamping plate and a second clamping plate, the first clamping plate and the second clamping plate are respectively located on both sides of the supporting portion and are both perpendicular to the supporting portion, and the distance between the first clamping plate and the second clamping plate is adapted to the width of the mobile phone.

[0014] Furthermore, it also includes: a support platform for supporting the angle measurement fixture.

[0015] On the other hand, the present invention provides a measurement method of the prism refractive index measurement device based on the above-mentioned mobile phone APP, comprising:

[0016] Step 1: Place the mobile phone close to the first refractive edge of the prism to be measured, and initialize the angle measured by the mobile phone to zero;

[0017] Step 2: Fix the prism and place the phone close to the second refractive edge of the prism. The angle measured by the phone is the prism angle.

[0018] Step 3: Fix the mobile phone to the angle measurement fixture;

[0019] Step 4: Adjust the angle measurement fixture so that the laser emitted by the laser source passes through the collimating slit and hits the screen. The location of the spot formed by the laser on the screen at this time is recorded as point B, and the angle measured by the mobile phone at this time is initialized to zero;

[0020] Step 5: Fix the laser source and the screen and place the prism on the rotating platform;

[0021] Step 6: Rotate the rotating platform to find the position of the light spot closest to point B, where the laser emitted by the laser source is refracted by the prism and hits the screen. The position of the light spot closest to point B is recorded as point C.

[0022] Step 7: Fix the laser source, screen and rotating platform and proceed to step 3;

[0023] Step 8: Adjust the angle measurement fixture so that the laser refracted by the prism passes through the collimating slit and hits point C on the screen. The angle measured by the mobile phone is the minimum deflection angle.

[0024] Step 9: Obtain the prism refractive index according to the prism angle and the minimum deflection angle.

[0025] Beneficial effects of the present invention:

[0026] Compared with the spectrometer used in the traditional method of measuring the refractive index of a prism (the spectrometer has a relatively complex structure, and the adjustment process when measuring the angle is too cumbersome and complicated), the prism refractive index measuring device based on a mobile phone provided by the present invention, except for the indispensable laser source, the measuring device of the embodiment of the present invention only includes a rotating platform and a collimating slit, both of which have a simple structure and are easy to manufacture, which greatly saves costs, and in the actual angle measurement process, the measurement operation is simple and quick.

[0027] Compared with the traditional measurement method of measuring the refractive index of a prism using a spectrometer (when using a spectrometer to measure the angle, the adjustment process of the spectrometer is too cumbersome and complicated), the prism refractive index measurement method based on a mobile phone provided by the present invention realizes the two major functions of angle measurement and refractive index calculation by utilizing the gyroscope sensor and accelerometer of the mobile phone applied to the APP, eliminating the manual calculation link, and the measurement method is simple and fast. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 One of the structural schematic diagrams of a prism refractive index measuring device based on a mobile phone APP provided in an embodiment of the present invention;

[0029] Figure 2 The second structural schematic diagram of the device for measuring the refractive index of a prism based on a mobile phone APP provided in an embodiment of the present invention;

[0030] Figure 3 A cross-sectional view of a rotating platform provided in an embodiment of the present invention;

[0031] Figure 4 A schematic diagram of the structure of an angle measuring fixture provided by an embodiment of the present invention;

[0032] Figure 5 A schematic diagram of a process for measuring the refractive index of a prism based on a mobile phone APP provided in an embodiment of the present invention;

[0033] Figure numerals: 1 is a laser source; 2 is a rotating platform; 3 is an angle measuring fixture; 4 is a mobile phone; 5 is a prism; 21 is a base plate; 22 is a supporting shaft; 23 is a turntable; 24 is a groove; 25 is a through hole; 26 is a two-stage frustum; 31 is a clamping part; 32 is a supporting part; 33 is a cross-shaped protrusion; 311 is a first clamping plate; 312 is a second clamping plate. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] At present, all smart phones are integrated with gyroscope sensors and accelerometers. The working principle of gyroscope sensor angle measurement is: the gyroscope sensor is used to measure the angle of rotation of the mobile phone in the horizontal plane (the angle of rotation around the Z axis). The gyroscope sensor outputs an angular velocity signal, and the angle can only be obtained after the angular velocity is integrated over time. The characteristics are good dynamic performance and poor static performance. The working principle of accelerometer angle measurement: Commonly used MEMS accelerometers are divided into three types: piezoelectric, capacitive and thermal. Taking the piezoelectric MEMS accelerometer as an example (the other two types are not repeated), the piezoelectric MEMS accelerometer uses the piezoelectric effect. There is a mass block supported by a rigid body inside it. When there is movement, the mass block will generate pressure, the rigid body will generate strain, and the acceleration will be converted into an electrical signal output. When the posture of the mobile phone in space is different, by measuring the oblique acceleration of the mobile phone plane, according to the principle of orthogonal decomposition and comparing it with the vertical gravity acceleration, the inclination angle of the mobile phone plane with the X-axis or Y-axis direction can be calculated. The characteristics are good static performance and poor dynamic performance.

[0036] The present invention obtains gyroscope sensor data and accelerometer data based on a mobile phone APP, and the angle measurement can be achieved by fusing the two data.

[0037] Example 1

[0038] The embodiment of the present invention provides a prism refractive index measuring device based on a mobile phone APP, the measuring device comprising: a laser source 1, a rotating platform 2 and an angle measuring fixture 3; the laser source 1 is used to output laser light; the rotating platform 2 is used to adjust the direction of the prism 5 to be measured relative to the laser light; the angle measuring fixture 3 is used to measure the first light direction of the laser before being refracted by the prism 5 and the second light direction of the laser after being refracted by the prism 5 using a mobile phone 4. The laser source 1 can be a helium-neon laser.

[0039] The rotating platform 2 includes a bottom plate 21, a support shaft 22 fixed on the bottom plate 21, and a turntable 23 that can rotate along the support shaft 22, and the turntable 23 is provided with a groove 24 for fixing the prism 5. A through hole 25 is provided on the support shaft 22, and a two-stage truncated cone 26 is provided in the middle of the turntable 23, and the small diameter end of the two-stage truncated cone 26 matches the through hole 25. The groove 24 is a triangular groove provided in the middle of the turntable 23.

[0040] The angle measuring fixture 3 includes a clamping portion 31 for fixing the mobile phone 4, a supporting portion 32 located above the clamping portion 31, and a cross-shaped protrusion 33 arranged on the supporting portion 32, wherein the cross-shaped protrusion 33 is provided with a collimating slit, and the clamping portion 31, the supporting portion 32 and the cross-shaped protrusion 33 are integrally formed. The clamping portion 31 includes a first clamping plate 311 and a second clamping plate 312, wherein the first clamping plate 311 and the second clamping plate 312 are respectively located on both sides of the supporting portion 32 and are both perpendicular to the supporting portion 32, and the distance between the first clamping plate 311 and the second clamping plate 312 is adapted to the width of the mobile phone 4.

[0041] In actual application, in order to make the angle measuring fixture 3 adapt to the height of the laser source 1, a support platform for supporting the angle measuring fixture 3 can also be set up. The support platform can adopt an existing structure that can play a supporting role, or a structure similar to the rotating platform 2. The difference is that there is no need to design a groove 24 on the support platform.

[0042] Compared with the spectrometer used in the traditional measurement method of the prism refractive index (the spectrometer structure is relatively complex, and the adjustment process when measuring the angle is too cumbersome and complicated), current smart phones are generally equipped with gyroscope sensors and accelerometers. The present invention is based on the mobile phone APP and uses the gyroscope sensor and accelerometer of the mobile phone to measure the angle; a collimation slit is set on the angle measurement fixture, and the direction of the laser light is determined by the slender slit collimation method. The prism refractive index measurement device based on the mobile phone provided by the present invention removes the indispensable laser source. The measurement device of the embodiment of the present invention only includes a rotating platform and an angle measurement fixture. The two structures are simple and easy to make, and can be directly printed by a 3D printer, which greatly saves costs. In the actual angle measurement process, the measurement operation is simple and fast.

[0043] Example 2

[0044] The embodiment of the present invention provides a method for measuring the refractive index of a prism based on a mobile phone, the method comprising the following steps:

[0045] S101: placing a mobile phone close to a first refractive edge of the prism to be measured, and initializing the angle measured by the mobile phone to zero;

[0046] S102: fix the prism and place the mobile phone close to the second refractive edge of the prism. The angle measured by the mobile phone is the prism angle.

[0047] S103: Fixing the mobile phone and the angle measurement fixture;

[0048] S104: Adjust the angle measurement fixture so that the laser emitted by the laser source hits the screen through the collimating slit, record the position of the light spot formed by the laser on the screen as point B, and initialize the angle measured by the mobile phone to zero;

[0049] S105: Fix the laser source and the screen and place the prism on a rotating platform;

[0050] S106: rotating the rotating platform to find the position of the light spot closest to point B, which makes the laser emitted by the laser source hit the screen after being refracted by the prism. The position of the light spot closest to point B is recorded as point C;

[0051] S107: Fix the laser source, screen and rotating platform and execute step S103.

[0052] S108: Adjust the angle measurement fixture so that the laser refracted by the prism passes through the collimating slit and hits point C on the screen. At this time, the angle measured by the mobile phone is the minimum deflection angle.

[0053] S109: Obtaining a prism refractive index according to the prism angle and the minimum deflection angle.

[0054] Example 3

[0055] For example, taking a prism with a prism angle of 60 degrees as an example, during the measurement process, a helium-neon laser is used as the laser source, and the measurement method is as follows:

[0056] S201: placing the mobile phone close to a refraction edge of the prism and initializing the mobile phone APP angle to zero;

[0057] S202: Fix the prism and place the mobile phone close to the other refractive edge of the prism. The prism angle can be directly read as 60 degrees.

[0058] S203: using a helium-neon laser as a laser source to measure the minimum deflection angle of the laser after being refracted twice by a prism;

[0059] Specifically, the prism is fixed inside the triangular groove of the rotating platform, the size of the triangular groove matches the size of the cross section of the prism; then, the rotating platform is continuously adjusted until the minimum deflection angle is found; then, the mobile phone is fixed to the angle measurement fixture, and the direction of the light ray with the minimum deflection angle is determined by the collimating slit, and the angle measured by the mobile phone APP at this time is initialized to zero;

[0060] S204: Take out the prism, fix the HeNe laser, then fix the mobile phone and the angle measurement fixture, and use the collimating slit to determine the direction of the incident light;

[0061] S205: At this time, the angle measured by the mobile phone APP is the minimum deflection angle, which is 38 degrees.

[0062] S206: According to the prism angle A (A = 60 degrees) and the minimum deflection angle δ min (δ min =38 degrees), the refractive index n of the prism can be calculated according to the following refractive index calculation formula.

[0063]

[0064] Compared with the traditional measurement method of measuring the refractive index of a prism using a spectrometer (when using a spectrometer to measure the angle, the adjustment process of the spectrometer is too cumbersome and complicated), the prism refractive index measurement method based on a mobile phone APP provided by the present invention has the following advantages: by utilizing the mobile phone APP based on the gyroscope sensor and accelerometer of the mobile phone to realize the two major functions of angle measurement and refractive index calculation, the manual calculation link is eliminated, and the measurement method is simple and fast.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A measuring method of a prism refractive index measuring device based on a mobile phone APP, characterized in that: The measuring device comprises: a laser source, a rotating platform and an angle measuring fixture; the laser source is used to output laser light; the rotating platform is used to adjust the direction of the prism to be measured relative to the laser light; the angle measuring fixture is used to measure the direction of the first light before the laser is refracted by the prism and the direction of the second light after the laser is refracted by the prism using a mobile phone; correspondingly, the measuring method comprises: Step 1: Place the mobile phone close to the first refractive edge of the prism to be measured, and initialize the angle measured by the mobile phone to zero; Step 2: Fix the prism and place the phone close to the second refractive edge of the prism. The angle measured by the phone is the prism angle. Step 3: Fix the mobile phone to the angle measurement fixture; Step 4: Adjust the angle measurement fixture so that the laser emitted by the laser source passes through the collimating slit and hits the screen. The location of the spot formed by the laser on the screen at this time is recorded as point B, and the angle measured by the mobile phone at this time is initialized to zero; Step 5: Fix the laser source and the screen and place the prism on the rotating platform; Step 6: Rotate the rotating platform to find the position of the light spot closest to point B, where the laser emitted by the laser source is refracted by the prism and hits the screen. The position of the light spot closest to point B is recorded as point C. Step 7: Fix the laser source, screen and rotating platform and proceed to step 3; Step 8: Adjust the angle measurement fixture so that the laser refracted by the prism passes through the collimating slit and hits point C on the screen. The angle measured by the mobile phone is the minimum deflection angle. Step 9: Obtain the prism refractive index according to the prism angle and the minimum deflection angle.

2. The measuring method according to claim 1, characterized in that: The rotating platform comprises a bottom plate, a supporting shaft fixed on the bottom plate and a rotating disk rotatable along the supporting shaft, wherein a groove for fixing the prism is arranged on the rotating disk.

3. The measuring method according to claim 2, characterized in that: A through hole is provided on the support shaft, and a two-section frustum is provided in the middle of the turntable, wherein the small-diameter end of the two-section frustum matches the through hole.

4. The measuring method according to claim 3, characterized in that: The groove is a triangular groove arranged in the middle of the rotating disk.

5. The measuring method according to claim 1, characterized in that: The angle measuring fixture comprises a clamping portion for fixing a mobile phone, a supporting portion located above the clamping portion, and a cross-shaped protrusion arranged on the supporting portion, wherein the cross-shaped protrusion is provided with a collimating slit, and the clamping portion, the supporting portion and the cross-shaped protrusion are integrally formed.

6. The measuring method according to claim 5, characterized in that: The clamping part includes a first clamping plate and a second clamping plate, the first clamping plate and the second clamping plate are respectively located on both sides of the supporting part and are perpendicular to the supporting part, and the distance between the first clamping plate and the second clamping plate is adapted to the width of the mobile phone.

7. The measuring method according to claim 5, characterized in that: The measuring device further comprises: a supporting platform for supporting the angle measuring fixture.

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