Nanoscale infinitesimal displacement measuring device based on novel optical path double range and non-localized interference

Abstract

The invention relates to a nanoscale infinitesimal displacement measuring device based on novel optical path double range and non-localized interference, which comprises a light source, an optical path amplification system, an optical path interference system and a data acquisition and processing system, and is characterized in that the optical path amplification system comprises a parallel plane mirror, the parallel plane mirror comprises a fixed mirror and a movable mirror, and the movable mirror generates infinitesimal displacement relative to the fixed mirror; the light path interference system comprises a first spectroscope, a second spectroscope, a first plane mirror, a second plane mirror and a convex lens, parallel plane mirrors are arranged between the first spectroscope and the second spectroscope, the first plane mirror is arranged below the first spectroscope, the second plane mirror is arranged below the second spectroscope, and the convex lens is arranged on the rear side of the second spectroscope. A data acquisition processing system is arranged behind the convex lens. Displacement is captured through the interference system and the optical path amplification system, the optical detection sensitivity is improved, the detection stability is remarkably improved in combination with the optical path interference system, and the nanoscale infinitesimal displacement measurement requirement is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-displacement detection, and in particular to a nanometer-level micro-displacement measurement device based on a new optical path magnification and non-localized interference. BACKGROUND

[0002] With the progress of micro-displacement measurement technology, nanometer-scale displacement detection puts forward more stringent technical requirements for system sensitivity and resolution capability. This has given rise to the need to develop detection devices with higher stability and measurement accuracy to meet the accurate characterization of micro-displacement in industrial manufacturing and scientific experiments.

[0003] Micro-displacement measurement can be divided into optical measurement and electrical measurement, each with its own advantages and disadvantages. Electrical measurement is relatively low in cost, but has low resolution, is easily affected by temperature drift and electromagnetic noise, and contact measurement may cause damage to the sample. In contrast, optical measurement, although more expensive, has the advantages of simple principle and effective solution to the above problems. Therefore, optical measurement has more advantages in high-precision measurement.

[0004] As an optical measurement device, the Michelson interferometer has the advantages of high sensitivity and non-contact measurement in micro-displacement measurement, but is limited by the resolution of λ / 2, making it difficult to meet the accuracy requirements of modern nanometer-level micro-displacement measurement. Therefore, a detection system with higher accuracy is needed. SUMMARY

[0005] To solve the problem that existing optical measurement devices cannot meet the needs of nanometer-level micro-displacement measurement, the present application proposes a nanometer-level micro-displacement measurement device based on a new optical path magnification and non-localized interference. The displacement is captured by an optical path magnification system to improve the sensitivity of optical detection, the stability of detection is significantly improved by combining an optical path interference system, and data processing is performed by a data acquisition and processing system to meet the needs of nanometer-level micro-displacement measurement.

[0006] To achieve the above purpose, the present application proposes a nanometer-level micro-displacement measurement device based on a new optical path magnification and non-localized interference, which includes an optical path detection module. The optical path detection module includes a light source, an optical path magnification system, an optical path interference system and a data acquisition and processing system. The optical path magnification system includes a parallel plane mirror, the parallel plane mirror includes a fixed mirror and a moving mirror, and the moving mirror moves relative to the fixed mirror.

[0007] The optical path interference system includes a first beam splitter, a second beam splitter, a first plane mirror, a second plane mirror and a convex lens. The parallel plane mirror is arranged between the first beam splitter and the second beam splitter, the first plane mirror is arranged below the first beam splitter, the second plane mirror is arranged below the second beam splitter, the convex lens is arranged at the rear side of the second beam splitter, and the data acquisition and processing system is arranged at the rear side of the convex lens.

[0008] Further, the first beam splitter, the second beam splitter, the first plane mirror, the second plane mirror, the convex lens, the fixed mirror and the movable mirror are provided with optical adjustment frames for adjusting the attitudes of the first beam splitter, the second beam splitter, the first plane mirror, the second plane mirror, the convex lens, the fixed mirror and the movable mirror.

[0009] The first beam splitter and the second beam splitter comprise half-transmission half-reflection mirrors.

[0010] The parallel plane mirror comprises a high-reflection parallel mirror.

[0011] The provision of the optical adjustment frames can accurately adjust the attitudes (such as the pitch angle and the horizontal angle) of the optical elements, ensure the alignment accuracy of the optical path, and improve the system stability.

[0012] Further, the light source is incident on the first beam splitter at an angle of 45°, the first beam splitter divides the incident light into transmitted light L1 and reflected light L2, the transmitted light L1 enters the high-reflection parallel plane mirror, reaches the second beam splitter, the reflected light L2 is transmitted to the first plane mirror, is reflected by the second plane mirror through the attenuator after reflection, and finally reaches the second beam splitter, the reflected light L2 and the transmitted light L1 form two convergent lights after passing through the convex lens, the two lights are respectively focused on two different points to generate two convergent points S1 and S2, the two lights are coherent laser, thus forming two coherent point light sources S1 and S2, and further forming a non-local interference fringe in space.

[0013] The data acquisition and processing system acquires the non-local interference fringe image to generate distance data.

[0014] The design of the light path amplification (multiple reflections of the parallel plane mirror) of the transmitted light L1 and the reference light path of the reflected light L2 makes the two lights form a non-local interference fringe after passing through the convex lens. The non-local interference fringe stably exists in space, reduces the limitation on the observation position, and enhances the anti-interference ability of the system; the two electric light sources formed by the focusing of the convex lens ensure that the interference fringe is clear and distinguishable, and the analysis of the fringe by the data acquisition and processing system realizes the accurate conversion of the displacement amount to the optical path difference information, which provides a direct basis for the calculation of the nanoscale micro displacement.

[0015] Further, the first plane mirror and the second plane mirror are provided with an attenuator. The provision of the attenuator ensures that the intensities of the two lights are similar, and avoids that the interference fringe is blurred due to the strong substrate light.

[0016] Further, the measurement verification system comprises a voltage driving system for driving the measured object, and the voltage driving system comprises an IT6332A three-way programmable direct-current power supply.

[0017] The IT6332A three-way programmable direct current power supply realizes voltage drive control, and can accurately adjust the voltage applied to the measured object.

[0018] Further, the light source comprises a helium-neon laser.

[0019] Further, the data acquisition and processing system comprises a CCD module and a host computer, the CCD module is used for acquiring non-localized interference fringe images, the output end of the CCD module is electrically connected to the host computer, and the host computer is used for analyzing the fringe movement through a Python program.

[0020] The CCD module efficiently acquires interference fringe images, ensuring clear capture of fringe details; the host computer analyzes the fringe movement through a Python program, realizing fringe movement counting.

[0021] Through the above technical solution, the present application has the following advantages:

[0022] 1. The present application comprises an optical path amplification system, a voltage drive system, an optical path interference system and a data acquisition and processing system, wherein the optical path amplification system is based on parallel plane mirrors (fixed mirror and movable mirror) design, so that the laser beam is reflected multiple times between the two mirrors to realize optical path amplification, and the sensitivity of micro displacement measurement is improved, providing core technical support for nanoscale micro displacement detection.

[0023] 2. The present application maintains the non-contact and high-precision advantages of optical measurement, and solves the limitations of traditional measurement techniques in nanoscale micro displacement detection: on the one hand, optical path amplification and non-localized interference design significantly improve measurement resolution and system stability, meeting the needs of nanoscale micro displacement measurement; on the other hand, through efficient acquisition and analysis, it provides a reliable measurement method for precision and ultra-precision fields such as micro positioning and micro deformation measurement, and has strong engineering application value. BRIEF DESCRIPTION OF DRAWINGS

[0024] Fig. 1It is a measurement device principle diagram of a nanoscale micro displacement measurement device based on a new optical path magnification and non-local interference according to the application;

[0025] Fig. 2 It is an optical path magnification principle diagram of a nanoscale micro displacement measurement device based on a new optical path magnification and non-local interference according to the application;

[0026] Fig. 3 It is an RGB change curve diagram of a nanoscale micro displacement measurement device based on a new optical path magnification and non-local interference according to the application;

[0027] Fig. 4 It is a non-local interference fringe experiment phenomenon diagram of a nanoscale micro displacement measurement device based on a new optical path magnification and non-local interference according to the application.

[0028] The figure reference: 1 is a piezoelectric ceramic, 2 is a light source, 3 is an optical path magnification system, 301 is a fixed mirror, 302 is a moving mirror, 4 is a voltage driving system, 5 is an optical path interference system, 501 is a first beam splitter, 502 is a second beam splitter, 503 is a first plane mirror, 504 is a second plane mirror, 505 is a convex lens, 6 is a data acquisition and processing system, 601 is a CCD module, 602 is an upper computer, 7 is an attenuator. DETAILED DESCRIPTION

[0029] Example 1

[0030] As Figs. 1-4 shown, a nanoscale micro displacement measurement device based on a new optical path magnification and non-local interference, comprising an optical path detection module, the optical path detection module comprises a light source 2, an optical path magnification system 3, an optical path interference system 5 and a data acquisition and processing system 6, the optical path magnification system 3 comprises parallel plane mirrors, the parallel plane mirrors comprise a fixed mirror 301 and a moving mirror 302, the moving mirror 302 produces a micro displacement relative to the fixed mirror 301.

[0031] The optical path interference system 5 comprises a first beam splitter 501, a second beam splitter 502, a first plane mirror 503, a second plane mirror 504 and a convex lens 505, the parallel plane mirrors are arranged between the first beam splitter 501 and the second beam splitter 502, the first plane mirror 503 is arranged below the first beam splitter 501, the second plane mirror 504 is arranged below the second beam splitter 502, the convex lens 505 is arranged at the rear side of the second beam splitter 502, and the data acquisition and processing system 6 is arranged at the rear side of the convex lens 505.

[0032] The first beam splitter 501, the second beam splitter 502, the first plane mirror 503, the second plane mirror 504, the convex lens 505, the fixed mirror 301 and the movable mirror 302 are all provided with optical adjustment frames for adjusting the postures of the first beam splitter 501, the second beam splitter 502, the first plane mirror 503, the second plane mirror 504, the convex lens 505, the fixed mirror 301 and the movable mirror 302.

[0033] The first beam splitter 501 and the second beam splitter 502 are half-transmission half-reflection mirrors.

[0034] The parallel plane mirror comprises a high-reflection parallel mirror.

[0035] The first plane mirror 503 and the second plane mirror 504 are provided with an attenuator 7.

[0036] The light source 2 is incident on the first beam splitter 501 at an angle of 45°, the first beam splitter 501 divides the incident light into transmitted light L1 and reflected light L2, the transmitted light L1 enters the high-reflection parallel plane mirror, reaches the second beam splitter 502, the reflected light L2 is transmitted to the first plane mirror 503, is reflected after passing through the attenuator 7, is reflected by the second plane mirror 504, and finally reaches the second beam splitter 502, the reflected light L2 and the transmitted light L1 form two convergent lights after passing through the convex lens 505, the two lights are respectively focused on two different points, two convergent points S1 and S2 are generated, the two lights are coherent laser, thus two coherent point light sources S1 and S2 are formed, and non-local interference fringes are formed in space.

[0037] The data acquisition and processing system 6 acquires non-local interference fringe images to generate distance data.

[0038] Further comprising a measurement verification system, the measurement verification system comprises a voltage driving system 4 for driving the measured object, and the voltage driving system 4 comprises an IT6332A three-way programmable direct-current power supply.

[0039] The light source 2 comprises a helium-neon laser.

[0040] The data acquisition and processing system 6 comprises a CCD module 601 and a host computer 602, the CCD module 601 is used for acquiring non-local interference fringe images, an output end of the CCD module 601 is electrically connected to the host computer 602, and the host computer 602 is used for analyzing the movement of the fringes through a Python program.

[0041] Embodiment 2

[0042] Based on the non-local interference fringe measurement device based on the new optical path magnification and non-local interference in embodiment 1, the detection effect of the present application is verified in this embodiment. The measured object in this embodiment is a piezoelectric ceramic 1.

[0043] Experimental steps:

[0044] 1. Build a new type of light path based on the displacement measurement device of nanoscale micro displacement measurement device based on non-local interference;

[0045] 2. Turn on the helium-neon laser power, and the outlet end is in front of the first beam splitter 501, so that the light source is strong and uniform on the first beam splitter 501;

[0046] 3. Adjust the pitch angle of the first beam splitter 501, the second beam splitter 502, the first plane mirror 503, the second plane mirror 504, the fixed mirror 301 and the moving mirror 302 in turn, and ensure that the light path is roughly parallel to the ground;

[0047] 4. Adjust the horizontal angle of the fixed mirror 301 and the moving mirror 302 to ensure that the two front mirrors are strictly parallel;

[0048] 5. Adjust the second beam splitter 502 again, and use the white screen to ensure that the light spot appears non-local interference fringes;

[0049] 6. After ensuring that the light spots are all coincided, make the observation screen appear bright and dark non-local interference fringes, replace the observation screen with the CCD module 601, and fine-tune the CCD module 601 to make the upper computer 602 display clearly display the non-local interference fringes;

[0050] 7. Connect the piezoelectric ceramic 1 with the IT6332A three-way programmable DC power supply through the wire, turn on the IT6332A three-way programmable DC power supply switch, and use the upper computer 602 to control the power output voltage;

[0051] 8. Run the voltage drive program to record the current voltage value every 10 non-local interference fringes, and use the upper computer 602 to record the image output by the CCD module 601, which can be observed on the display to observe the periodic change of the non-local interference fringes;

[0052] 9. According to the recorded image, use Python program to record and draw the RGB change curve graph of the fringes in a region;

[0053] 10. Repeat the measurement of three groups of experimental data.

[0054] According to the collected data, the measurement results of the displacement of the piezoelectric ceramic are recorded, and the voltage value applied to the two ends of the piezoelectric ceramic is recorded once every 10 non-local interference fringes during the experiment. When the wavelength of light is 650nm, the measurement results are shown in the table:

[0055] Table 1 Relationship between voltage and displacement of piezoelectric ceramic

[0056]

[0057] As shown in Table 1, the light path magnification device has an incident angle of 15 degrees and 32 times of reflection, and the movement of each non-local interference fringe represents a micro displacement of 21.0 nm. In the experiment, the voltage value applied to both ends of the piezoelectric ceramic is recorded once every ten non-local interference fringes are moved, and when 130 non-local interference fringes are moved, the applied voltage is about 57.178 V. It can be inferred that in actual work, the piezoelectric constant of the piezoelectric ceramic is about 47.7 nm / V. The precision of the present application reaches 21.0 nm when the number of reflections is 32, and the displacement detection effect is good.

[0058] Example 3

[0059] Based on the nanoscale micro displacement measurement device based on a new light path magnification and non-local interference in Example 1, the distance detection is described in this embodiment, and the measured object in this embodiment is a piezoelectric ceramic 1.

[0060] Experimental steps:

[0061] 1. Build a nanoscale micro displacement measurement device based on a new light path magnification and non-local interference;

[0062] 2. Turn on the helium-neon laser power supply, and place the outlet end in front of the first beam splitter 501 to make the light source strong and uniform incident on the first beam splitter 501;

[0063] 3. Adjust the pitch angles of the first beam splitter 501, the second beam splitter 502, the first plane mirror 503, the second plane mirror 504, the fixed mirror 301 and the moving mirror 302 in turn to ensure that the light path is roughly parallel to the ground;

[0064] 4. Adjust the horizontal angles of the fixed mirror 301 and the moving mirror 302 to ensure that the two front mirrors are strictly parallel;

[0065] 5. Adjust the second beam splitter 502 again, and use the white screen to ensure that the light spot appears non-local interference fringes;

[0066] 6. After ensuring that the light spots are all coincident, make the observation screen appear non-local interference fringes with light and dark, replace the observation screen with a CCD module 601, and fine-tune the CCD module 601 to make the host computer 602 display clearly show the non-local interference fringes;

[0067] 7. Connect the piezoelectric ceramic 1 with the IT6332A three-way programmable DC power supply through the wire, turn on the IT6332A three-way programmable DC power supply switch, and use the host computer 602 to control the power output voltage to gradually increase the voltage from 0 V to 60 V;

[0068] 8. Running voltage driver program, using host computer 602 to record the image output by CCD module 601, and observing the periodic change of non-localized interference fringes on the display;

[0069] 9. According to the recorded image, using Python program to record the number of non-localized interference fringe movement when the voltage increases to 60V.

[0070] 10. Repeating the measurement of 8 groups of data.

[0071] The experimental data is shown in Table 2

[0072] Table 2 Fringe movement number and displacement amount U=60V

[0073]

[0074] In Table 2, the displacement amount difference of 1-8 detections is small, indicating that the nanoscale micro displacement measurement device based on the new optical path magnification and non-localized interference has good stability.

[0075] The above-described embodiments are only preferred embodiments of the present application and are not intended to limit the scope of the present application. Any equivalent changes or modifications made to the structure, features and principles described in the patent scope of the present application should be included in the patent scope of the present application.

Claims

1. A nanometer scale micro-displacement measurement device based on a new optical path magnification and non-local interference, comprising an optical path detection module, characterized in that, The light path detection module comprises a light source (2), a light path amplification system (3), a light path interference system (5) and a data acquisition and processing system (6), the light path amplification system (3) comprises parallel plane mirrors, the parallel plane mirrors comprise fixed mirrors (301) and movable mirrors (302), and the movable mirrors (302) move relative to the fixed mirrors (301); The light path interference system (5) comprises a first beam splitter (501), a second beam splitter (502), a first plane mirror (503), a second plane mirror (504) and a convex lens (505), the parallel plane mirrors are arranged between the first beam splitter (501) and the second beam splitter (502), the first plane mirror (503) is arranged below the first beam splitter (501), the second plane mirror (504) is arranged below the second beam splitter (502), the convex lens (505) is arranged at the rear side of the second beam splitter (502), and the data acquisition and processing system (6) is arranged at the rear side of the convex lens (505).

2. The nanometer scale micro-displacement measurement device based on new optical path magnification and non-localized interference according to claim 1, characterized in that, The first beam splitter (501), the second beam splitter (502), the first plane mirror (503), the second plane mirror (504), the convex lens (505), the fixed mirrors (301) and the movable mirrors (302) are all provided with optical adjustment frames, and the optical adjustment frames are used for adjusting the postures of the first beam splitter (501), the second beam splitter (502), the first plane mirror (503), the second plane mirror (504), the convex lens (505), the fixed mirrors (301) and the movable mirrors (302). The first beam splitter (501) and the second beam splitter (502) comprise half-transmission half-reflection mirrors. The parallel plane mirrors comprise high-reflection parallel mirrors.

3. The nanometer scale micro-displacement measurement device based on new optical path magnification and non-localized interference according to claim 2, characterized in that, An attenuator (7) is arranged between the first plane mirror (503) and the second plane mirror (504).

4. The nanometer scale micro-displacement measurement device based on new optical path magnification and non-localized interference according to claim 3, characterized in that, The light source (2) is incident on the first beam splitter (501) at an angle of 45°, the first beam splitter (501) divides the incident light into transmitted light L1 and reflected light L2, the transmitted light L1 enters the high-reflection parallel plane mirror, reaches the second beam splitter (502), the reflected light L2 is transmitted to the first plane mirror (503), is reflected after the first plane mirror (503), is reflected by the second plane mirror (504) through the attenuator (7), and finally reaches the second beam splitter (502), the reflected light L2 and the transmitted light L1 form two convergent lights after passing through the convex lens (505), the two lights are focused on two different points, two convergent points S1 and S2 are generated, the two lights are coherent laser, thus two coherent point light sources S1 and S2 are formed, and non-local interference fringes are formed in space; The data acquisition and processing system (6) acquires non-local interference fringe images to generate distance data.

5. The nanometer scale micro-displacement measurement device based on new optical path magnification and non-local interference according to claim 1, characterized in that, The measurement verification system comprises a voltage driving system (4) for driving the measured object, and the voltage driving system (4) comprises an IT6332A three-way programmable direct-current power supply.

6. The nanometer scale micro-displacement measurement device based on new optical path magnification and non-localized interference according to claim 1, characterized in that, The light source (2) comprises a helium-neon laser.

7. The nanometer scale micro-displacement measurement device based on new optical path magnification and non-local interference according to claim 1, characterized in that, The data acquisition processing system (6) comprises a CCD module (601) and a host computer (602), the CCD module (601) is used for acquiring non-localized interference fringe images, and an output end of the CCD module (601) is electrically connected with the host computer (602); the host computer (602) is used for analyzing fringe movement through a Python program.

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