Method and device for measuring micro deformation of object surface based on laser interference

Abstract

The invention discloses a method and a device for measuring micro-deformation of an object surface based on laser interference, and belongs to the technical field of precision measurement. The device can collect, process and output micro-deformation data in real time, real-time monitoring of object surface micro-deformation is achieved, laser light spots irradiate a micro-deformation area of the object surface, laser light can be reflected in different directions in the micro-deformation area, when the optical path difference meets the integral multiple of the wavelength of the object, the interference phenomenon can occur, and the object surface micro-deformation can be monitored in real time. And a light and dark alternate concentric circle-shaped stripe structure is formed. The technology is carried out on interference rings of a bright field, so that simple, efficient and high-precision deformation detection can be realized by utilizing the relationship between the number of laser interference rings and the deformation quantity of the surface of an object, and powerful support is provided for dynamic process control and real-time feedback.

Description

Technical Field

[0001] The present invention relates to the field of precision measurement technology, and in particular to a method and device for measuring micro-deformation of an object surface based on laser interference. Background Art

[0002] As a non-contact measurement method, laser interferometry technology has shown broad application prospects in the field of micro-deformation measurement due to its advantages such as high precision and high sensitivity. Most of the existing technologies use complex interference pattern analysis or phase demodulation methods to obtain deformation data. These methods are often complex in calculation, poor in real-time performance, and sensitive to environmental noise. Traditional measurement methods, such as contact measurement, are simple to operate, but have disadvantages such as insufficient accuracy and easy mechanical damage to samples, especially when measuring soft or fragile materials. These disadvantages are more obvious. Optical microscopes cannot be used to measure micro-deformations on the surface of objects, but can only observe deformations.

[0003] In particular, existing technologies face greater challenges in measuring micro-deformation on liquid surfaces. The dynamic characteristics of liquid surfaces require measurement methods to have extremely high sensitivity and real-time performance, but traditional measurement methods are difficult to meet these requirements. The number of interference rings, as an intuitive feature in the interference pattern, has a clear mathematical relationship with the deformation, but how to effectively use this relationship for precise measurement is still a problem that needs to be solved in current technology. Summary of the invention

[0004] The purpose of the present invention is to overcome the multiple deficiencies of the existing laser interferometry technology and to provide a method and device for measuring micro-deformation of an object surface based on laser interferometry.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A method for measuring micro-deformation of an object surface based on laser interferometry, which is used for measuring micro-deformation of a solid surface and a liquid surface, comprises the following steps:

[0007] S1. Use a laser light source capable of emitting highly monochromatic laser light to illuminate the surface of the object to be measured;

[0008] S2. The laser is reflected on the surface of the object to be measured, forming an interference pattern;

[0009] S3. Collect the interference pattern formed by the reflection through the image acquisition system and identify the interference ring;

[0010] S4. Calculate the deformation variable using the mathematical relationship between the number of interference rings and the deformation variable; the specific relationship is:

[0011] ;

[0012] in, is the shape variable, If is the number of interference rings, is the wavelength of the laser;

[0013] S5. Output micro-deformation data of the object surface.

[0014] Furthermore, the image acquisition system is any plane that can achieve diffuse reflection, and is used to capture the interference pattern formed by the reflection.

[0015] A device for measuring micro-deformation of an object surface based on laser interference, the device comprising: a laser light source for emitting high-monochromatic laser light to irradiate the surface of the object to be measured; an image acquisition system for collecting interference patterns formed by reflection; a data processing unit for analyzing the interference patterns, identifying the number of interference rings and calculating the deformation amount; a display output unit for displaying or outputting micro-deformation data; the device is suitable for measuring micro-deformation of solid surfaces and liquid surfaces.

[0016] Furthermore, the laser light source is any type of highly monochromatic laser light source.

[0017] Furthermore, the image acquisition system includes a camera, an image sensor or a similar device for capturing the interference pattern formed by the reflection.

[0018] Furthermore, the data processing unit includes a computer, a microprocessor or a similar device for analyzing the interference pattern, identifying the number of interference rings and calculating the deformation amount.

[0019] Furthermore, the display output unit includes a display, a printer or a similar device for displaying or outputting the micro-deformation data.

[0020] The beneficial effects of the present invention are:

[0021] (1) By utilizing the principle of laser interference and accurately identifying the number of interference rings, the present invention can achieve high-precision measurement of micro-deformation on the surface of an object, significantly improving the accuracy and reliability of the measurement data; the non-contact measurement method of laser irradiation and reflection interference effectively avoids the mechanical damage to the sample caused by traditional contact measurement, and is particularly suitable for surface micro-deformation measurement of fragile or sensitive materials; the device can collect, process and output micro-deformation data in real time, realizing real-time monitoring of micro-deformation on the surface of an object, and providing strong support for dynamic process control and real-time feedback;

[0022] (2) The present invention is not only applicable to the measurement of micro-deformation on solid surfaces, but also to the measurement of micro-deformation on liquid surfaces, showing a wide range of applicability and meeting the measurement needs in multiple fields such as scientific research, industrial production, and quality control;

[0023] (3) By directly utilizing the relationship between the number of interference rings and the deformation amount, the present invention simplifies the measurement process, reduces the operation complexity, and improves the measurement efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of the structure of a testing system for measuring micro-variations on the surface of an object based on laser interferometry provided in an embodiment of the present invention;

[0025] FIG2 is an interference ring diagram obtained by detecting PMMA (polymethyl methacrylate) samples with deformation amounts of 0.92 μm, 1.58 μm, 2.41 μm, 3.39 μm and 5.12 μm at three wavelengths of laser and an interference ring diagram obtained by Matlab simulation provided in Example 1 of the present invention;

[0026] FIG3(a), FIG3(b) and FIG3(c) are respectively linear fitting images of the relationship between the number of laser interference rings and the deformation amount of 405nm, 532nm and 633nm laser interference rings provided by embodiments of the present invention;

[0027] Figure 4 A schematic diagram of a monitoring system for real-time monitoring of micro-deformation on the surface of an object provided by an embodiment of the present invention;

[0028] FIG5(a), FIG5(b) and FIG5(c) are comparison diagrams of the interferometric measurement results of the solid convex deformation of the step meter provided in the embodiment of the present invention under 405nm, 532nm and 633nm lasers, and FIG5(d) is a general comparison diagram of the convex shape variables measured under 405nm, 532nm and 633nm lasers and the convex shape variables measured by the stage meter;

[0029] FIG6 (a), FIG6 (b) and FIG6 (c) are comparison diagrams of the interferometric measurement results of the concave deformation of a solid by the step meter provided in an embodiment of the present invention under 405nm, 532nm and 633nm lasers; FIG6 (d) is a general comparison diagram of the concave deformation variables measured under 405nm, 532nm and 633nm lasers and the concave deformation variables measured by the stage meter;

[0030] Figure 7 A comparison diagram of the results of (a) a concave deformation and (b) a convex deformation of a liquid surface measured by a translation stage and laser interferometry provided by an embodiment of the present invention;

[0031] In the figure: 1-laser light source, 2-reflector, 3-beam splitter, 4-light screen, 5-sample to be tested, 6-laser, 7-reflector, 8-beam splitter, 9-image acquisition system, 10-sample to be tested, 11-data processing system and display output unit. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0033] A method for measuring micro-deformation of an object surface based on laser interferometry is provided, which is used for measuring micro-deformation of a solid surface and a liquid surface, and comprises the following steps:

[0034] S1. Use a laser light source capable of emitting highly monochromatic laser light to illuminate the surface of the object to be measured;

[0035] S2. The laser is reflected on the surface of the object to be measured, forming an interference pattern;

[0036] S3. Collect the interference pattern formed by the reflection through the image acquisition system and identify the interference ring;

[0037] S4. Calculate the deformation variable using the mathematical relationship between the number of interference rings and the deformation variable; the specific relationship is:

[0038] ;

[0039] in, is the shape variable, If is the number of interference rings, is the wavelength of the laser;

[0040] S5. Output micro-deformation data of the object surface.

[0041] The image acquisition system is any plane that can achieve diffuse reflection, and is used to capture the interference pattern formed by reflection.

[0042] Provided is a device for measuring micro-deformation of an object surface based on laser interference, the device comprising: a laser light source for emitting a high-monochromatic laser to irradiate the surface of an object to be measured; an image acquisition system for collecting interference patterns formed by reflection; a data processing unit for analyzing the interference patterns, identifying the number of interference rings and calculating the deformation amount; and a display output unit for displaying or outputting micro-deformation data. The device is suitable for measuring micro-deformation of solid surfaces and liquid surfaces.

[0043] The laser light source is any type of highly monochromatic laser light source.

[0044] The image acquisition system includes a camera, an image sensor or a similar device for capturing the interference pattern formed by the reflection.

[0045] The data processing unit includes a computer, a microprocessor or a similar device for analyzing the interference pattern, identifying the number of interference rings and calculating the deformation amount.

[0046] The display output unit includes a display, a printer or similar equipment, which is used to display or output the micro-deformation data.

[0047] Embodiment 1:

[0048] This embodiment provides a method for measuring micro-deformation of a solid surface based on the relationship between the number of laser interference rings and the deformation amount.

[0049] like Figure 1 As shown, a laser light source 1 emits a highly monochromatic laser, which is reflected by a reflector 2 to the surface of a sample 5 to be tested that has been scanned by a step profiler. The micro-deformation of the solid surface causes the laser reflected from the surface to produce a phase change.

[0050] like Figure 1 As shown, the light screen 4 collects the laser reflected by the beam splitter 3 to form interference patterns under 633nm, 532nm and 405nm lasers, as shown in Figures 2(a) to 2(c). The data processing unit analyzes the interference pattern and identifies the number of interference rings.

[0051] As shown in Figure 3 (a) to Figure 3 (c), based on the mathematical relationship between the number of interference rings and the deformation amount, the micro-deformation data of the solid surface under 633nm, 532nm and 405nm lasers are calculated respectively.

[0052] As shown in Figures 5(a) to 5(c), five different convex deformations of solid surfaces were tested using a step meter under 405nm, 532nm and 633nm lasers, respectively. As shown in Figure 5(d), the values ​​of the deformation obtained are similar, indicating that this method can measure the convex deformation of the solid surface.

[0053] As shown in Figures 6(a) to 6(c), five different concave deformations of solid surfaces were tested using a step profiler under 405nm, 532nm and 633nm lasers, respectively. As shown in Figure 6(d), the values ​​of the deformation variables obtained are similar, indicating that this method can measure the concave deformation of the solid surface.

[0054] Embodiment 2:

[0055] This embodiment provides a method for measuring liquid surface micro-deformation based on the relationship between the number of laser interference rings and the deformation amount.

[0056] like Figure 1As shown, the laser light source 1 emits a highly monochromatic laser, which is reflected by the reflector 2 to the surface of the sample 5 to be tested which has been tested by the displacement stage. The liquid surface undergoes micro deformation under the influence of external factors such as fluid dynamics and temperature changes, causing the laser reflected from the surface to undergo phase changes.

[0057] like Figure 1 As shown, the light screen 4 collects the laser reflected by the beam splitter 3 to form interference patterns under 633nm, 532nm and 405nm lasers, as shown in Figures 2(a) to 2(c). The interference pattern is analyzed to identify the number of interference rings.

[0058] As shown in Figure 3 (a) to Figure 3 (c), based on the mathematical relationship between the number of interference rings and the deformation amount, the micro-deformation data of the solid surface under 633nm, 532nm and 405nm lasers are calculated.

[0059] like Figure 7 As shown, the concave and convex deformations of five different liquid surfaces were measured using a translation stage and a laser, respectively, and the deformation values ​​obtained were similar, indicating that this method can realize the measurement of micro-deformations of the liquid surface.

[0060] Embodiment three:

[0061] This embodiment provides a method for real-time monitoring of micro-deformation of an object surface based on the relationship between the number of laser interference rings and the deformation amount.

[0062] like Figure 4 As shown, the device operates continuously, and the laser light source 6 continuously emits highly monochromatic laser light, which directly irradiates the surface of the object to be measured.

[0063] like Figure 4 As shown, the image acquisition system 9 collects the laser reflected by the beam splitter 8 in real time at a high frame rate to form an interference pattern as shown in FIG. 2 .

[0064] As shown in Figure 3 (a) to Figure 3 (c), based on the mathematical relationship between the number of interference rings and the deformation amount, the micro-deformation data of the solid surface under 633nm, 532nm and 405nm lasers are calculated.

[0065] like Figure 4 As shown, the display output unit 11 updates the micro deformation data in real time, realizing real-time monitoring of the micro deformation of the surface of the object to be measured. This method is suitable for occasions requiring real-time monitoring, such as structural health monitoring, dynamic process control, etc.

[0066] By utilizing the principle of laser interference and accurately identifying the number of interference rings, the present invention can achieve high-precision measurement of micro-deformation on the surface of an object, significantly improving the accuracy and reliability of the measurement data; the non-contact measurement method of laser irradiation and reflection interference is adopted, which effectively avoids the mechanical damage to the sample caused by traditional contact measurement, and is particularly suitable for surface micro-deformation measurement of fragile or sensitive materials; the device can collect, process and output micro-deformation data in real time, realizes real-time monitoring of micro-deformation on the surface of an object, and provides strong support for dynamic process control and real-time feedback;

[0067] The present invention is not only applicable to the measurement of micro-deformation on solid surfaces, but also to the measurement of micro-deformation on liquid surfaces, showing a wide range of applicability and meeting the measurement needs in multiple fields such as scientific research, industrial production, and quality control.

[0068] By directly utilizing the relationship between the number of interference rings and the deformation amount, the present invention simplifies the measurement process, reduces the operation complexity, and improves the measurement efficiency.

[0069] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for measuring micro-deformation of an object surface based on laser interferometry, which is used for measuring micro-deformation of solid surfaces and liquid surfaces, characterized in that: The following steps are involved: S1. Use a laser light source to illuminate the surface of the object to be measured; S2. The laser is reflected on the surface of the object to be measured, forming an interference pattern; S3. Collect the interference pattern formed by the reflection through the image acquisition system and identify the interference ring; S4. Calculate the deformation variable using the mathematical relationship between the number of interference rings and the deformation variable; the specific relationship is: ； in, is the shape variable, is the number of interference rings, is the wavelength of the laser; S5. Output micro-deformation data of the object surface.

2. The method for measuring micro-deformation of an object surface based on laser interferometry according to claim 1, characterized in that: The image acquisition system is a plane that can achieve diffuse reflection and is used to capture the interference pattern formed by reflection.

3. A device for measuring micro-deformation of an object surface based on laser interferometry, characterized in that: include: A laser light source is used to emit a highly monochromatic laser to illuminate the surface of the object to be measured; an image acquisition system is used to collect the interference pattern formed by reflection; A data processing unit for analyzing the interference pattern, identifying the number of interference rings and calculating the deformation amount; Display output unit, used for displaying or outputting micro deformation data; The device is suitable for measuring micro-deformation of solid surfaces and liquid surfaces.

4. The device for measuring micro-deformation of an object surface based on laser interference according to claim 3, characterized in that: The laser light source is any type of high monochromatic laser.

5. The device for measuring micro-deformation of an object surface based on laser interference according to claim 3, characterized in that: The image acquisition system includes a camera, an image sensor or a similar device for capturing the interference pattern formed by the reflection.

6. The device for measuring micro-deformation of an object surface based on laser interference according to claim 3, characterized in that: The data processing unit includes a computer and a microprocessor, which are used to analyze interference patterns, identify the number of interference rings and calculate the deformation amount.

7. The device for measuring micro-deformation of an object surface based on laser interference according to claim 3, characterized in that: The display output unit includes a display and a printer, which are used to display or output micro-deformation data.

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