Two-dimensional grating type micro-deformation and micro-crack detection device

Abstract

The utility model relates to the technical field of mechanical detection, in particular to a two-dimensional grating type micro-deformation and micro-crack detection device, which comprises a polychromatic light spot light source, a convex lens, a two-dimensional grating, two industrial cameras and a shell, the polychromatic light spot light source emits incident light, the incident light is refracted into parallel polychromatic light through the convex lens, and the parallel polychromatic light irradiates on the two-dimensional grating to generate optical diffraction; transverse diffraction light and longitudinal diffraction light are generated in the transverse diffraction direction and the longitudinal diffraction direction respectively, then diffraction light images are received by two industrial cameras in the orthogonal direction and displayed as transverse diffraction light patterns and longitudinal diffraction light patterns respectively, and the industrial cameras receive specific images of a deformation area and display the specific images in the deformation area. The diffraction light image received by the industrial camera is processed so as to reversely deduce the deformation of the detected surface, and the micro-deformation and micro-crack detection device has no special requirements on the material surface and the material, does not influence the material performance, does not damage the material or the mechanical surface, and has the cost advantage compared with the current similar scheme.

Description

Technical Field

[0001] The utility model relates to the technical field of mechanical detection, in particular to a two-dimensional grating type micro-deformation and micro-crack detection device. Background Art

[0002] Two-dimensional grating is a kind of component that produces optical modulation in orthogonal directions. The two-dimensional grating material used in the utility model is a deformable material with a millimeter-level thickness and a two-dimensional grating structure on the surface. Its surface is a two-dimensional grating structure array with a grating period in the micron to submicron level and a depth in the micron to submicron level. Its appearance is generally a discrete point structure array in the shape of a circular, rectangular hole, column, cone, etc. and other special-shaped structures. Due to the presence of a point array with a submicron grating period on its surface, the two-dimensional grating can generate optical diffraction in two orthogonal directions respectively. Any position on the two-dimensional grating surface can generate diffracted light in any direction when irradiated by a light source. The wavelength of the diffracted light is related to the grating period, the incident angle, and the diffraction angle. Therefore, when the surface of the mechanical material has micro-deformation, micro-cracks, micro-protrusions, micro-grooves and other structures, the two-dimensional grating in contact with it will deform due to the contact, thereby causing the grating period, the incident angle, and the diffraction angle to change, thereby causing the diffracted light image to change. The three-dimensional structure of the surface of the mechanical material can be inferred through the change of the image, thereby realizing the detection of micro-deformation and micro-cracks.

[0003] Micro-deformation and micro-crack detection is generated for the surface measurement of many current engineering materials, precision machinery, and geotechnical structures. The flatness and finish of materials, machinery or structures are important indicators of their performance. The micro-deformation and micro-cracks on their surfaces will have a significant impact on the performance of the corresponding materials, machinery, and structures, and may even lead to failure, resulting in parts failure, material damage, structural damage and other problems. Therefore, high-precision micro-crack and micro-deformation detection tools are required. At present, the main detection methods for micro-deformation and micro-crack detection include visual detection, penetration detection, ultrasonic detection, magnetic particle detection, infrared thermal imaging and other detection methods. Among them, visual detection uses the naked eye or microscope to observe, and can observe cracks and deformations from millimeter to submillimeter level, with low accuracy. The penetration detection method has cumbersome steps and is time-consuming, and the penetration of the material during the detection process will have a certain impact on the performance of the material, and cannot be used for non-permeable materials. Ultrasonic detection has high measurement accuracy, but the cost is high, and the detection effect is affected by the acoustic properties and geometric shape of the material, and the material itself has high requirements. Magnetic particle detection can only be used for magnetic materials, and the process of applying a magnetic field may affect the performance of the material. Infrared thermal imaging detection has low accuracy, high cost, and high environmental requirements, so it cannot effectively detect microcracks. Utility Model Content

[0004] The purpose of the utility model is to provide a two-dimensional grating type micro-deformation micro-crack detection device, and the purpose is to solve the shortcomings of the current micro-deformation micro-crack detection method. In the prior art, the visual detection method has low accuracy, the penetration detection method has complicated steps, is time-consuming, and has limited materials, the ultrasonic detection results are too high and has high requirements for materials, the magnetic particle detection may affect the performance of the material itself, and the infrared thermal imaging detection method has high cost, low accuracy, and high environmental requirements. The purpose of the utility model is to overcome the shortcomings of the prior art and provide a detection device that can realize low-cost, high-precision, and real-time detection of tiny deformations and cracks.

[0005] To achieve the above-mentioned purpose, the utility model provides a two-dimensional grating type micro-deformation and micro-crack detection device, comprising a polychromatic point light source, a convex lens, a two-dimensional grating, two industrial cameras and a shell, wherein the shell is arranged outside the component to seal internal components, the convex lens is arranged below the polychromatic point light source to refract the incident light emitted by the point light source into parallel polychromatic light, the two-dimensional grating is arranged below the convex lens to diffract the parallel polychromatic light, and the two industrial cameras are sequentially arranged at two orthogonal side oblique directions of the two-dimensional grating to receive diffracted light images.

[0006] In one embodiment, the two-dimensional grating has an area of ​​5mm×5mm, the transverse and longitudinal grating periods are both 1μm, the depth is 0.7μm, the thickness is 1mm, the material is a circular two-dimensional discrete dot structure array of PDMS resin material, and the optional processing methods of the two-dimensional grating include nanoimprint lithography technology, vibration imprint processing technology, and vibration scratching processing technology. The two-dimensional grating used in the embodiment is manufactured by vibration imprint processing technology.

[0007] In one of the embodiments, the complex color point light source is a single point LED highlight light source installed at the focus.

[0008] In one of the embodiments, the image processing method is to first perform bilateral filtering on the received two-directional diffraction light images, then perform image enhancement and region extraction on the reference image and the diffraction light image, then integrate the regions and perform edge extraction and discretization, and finally solve the extracted contour to infer the strain distribution of the two-dimensional grating surface, thereby feeding back the micro-deformation and micro-cracks on the mechanical or material surface.

[0009] The utility model discloses a two-dimensional grating type micro-deformation micro-crack detection device, wherein the polychromatic light point light source emits incident light, passes through the convex lens, becomes parallel polychromatic light, and irradiates the two-dimensional grating to generate optical diffraction, and generates transverse diffraction light and longitudinal diffraction light in the transverse and longitudinal diffraction directions respectively, and then the diffraction light is received by the industrial cameras in two orthogonal directions, and is displayed as a transverse diffraction light pattern and a longitudinal diffraction light pattern respectively, so that when the two-dimensional grating contacts the micro-deformation micro-crack area, the industrial camera will receive a specific image of the deformation area, so as to detect the micro-deformation micro-crack area by means of the diffraction light and the deformation. The relationship between the two components is analyzed, and the diffraction light image received by the industrial camera is processed to infer the deformation of the two-dimensional grating, so as to feedback the micro-deformation of the mechanical surface and the three-dimensional morphology of the micro-cracks, thereby greatly improving the measurement accuracy, and realizing the detection of micro-cracks and micro-deformations from nanometer level to submicron level. The device is small in size and can adapt to the surface measurement of narrow spaces and tiny machines or materials. It has no special requirements for the material surface and material, will not affect the material performance, and will not damage the material or mechanical surface. It only uses light sources, lenses, two-dimensional gratings, and industrial cameras, and the cost is low.

[0010] The invention utilizes a high-precision contact measurement method of two-dimensional grating measurement. A deformable two-dimensional grating with a thickness of millimeters directly contacts the measured surface. The unevenness and cracks on the surface will cause the deformation of the two-dimensional grating, thereby changing the stress and strain distribution on the two-dimensional grating surface. When a parallel light source is irradiated to the two-dimensional grating surface, due to the different strain distribution on its surface, the industrial camera can receive the diffraction light image of the two-dimensional grating surface. Each pixel of the image reflects the deformation of the two-dimensional grating surface, wherein the influencing parameters are the grating period, the incident angle, and the diffraction angle. In this way, the micro-deformation and micro-crack morphology of the mechanical surface can be fed back through the diffraction light image received by the industrial camera, thereby realizing the surface micro-deformation or micro-crack detection with nanometer to submicron precision, and the accuracy is much higher than the prior art. This device only includes a light source, a lens, a two-dimensional grating, and a camera, and has a low cost and a small size. It can be applied to many materials or machines with narrow measurement space and small volume. In summary, the purpose of the utility model is to realize low-cost, high-precision, and real-time detection of tiny deformations and cracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0012] Figure 1 It is a principle diagram of a two-dimensional grating type micro-deformation and micro-crack detection device of the utility model.

[0013] Figure 2 It is the measurement deformation principle diagram and key parameters of the two-dimensional grating of the utility model.

[0014] Figure 3 This is a prototype diagram of the two-dimensional grating type micro-deformation and micro-crack detection device of the utility model.

[0015] 1-polychromatic point light source, 2-incident light, 3-convex lens, 4-parallel polychromatic light, 5-lateral diffraction light, 6-longitudinal diffraction light, 7-two-dimensional grating, 8-industrial camera, 9-longitudinal diffraction light pattern, 10-lateral diffraction light pattern, 11-lateral grating spacing, 12-longitudinal grating spacing, 13-lateral grating length, 14-longitudinal grating length, 15-grating thickness, 16-housing. DETAILED DESCRIPTION

[0016] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0017] See also Figures 1 to 3 ,in Figure 1 This is the principle diagram of the two-dimensional grating type micro-deformation and micro-crack detection device of the utility model. Figure 2 This is the measurement deformation principle diagram and key parameters of the two-dimensional grating of the utility model. Figure 3 This is a prototype diagram of the two-dimensional grating type micro-deformation and micro-crack detection device of the utility model.

[0018] See also Figure 3 The utility model provides a two-dimensional grating type micro-deformation micro-crack detection device, comprising a polychromatic light point light source 1, a convex lens 3, a two-dimensional grating 7, two industrial cameras 8 and a housing 16, wherein the housing 16 is arranged outside the other components.

[0019] See also Figure 3 The polychromatic point light source 1 used in this embodiment is a high-brightness single-point LED light source, and the focal length of the convex lens 3 is 10 mm. The convex lens 3 is arranged below the polychromatic point light source 1, so the parallel polychromatic light source 4 is formed by the incident light 2 emitted by the polychromatic point light source 1 after being refracted by the convex lens 3 placed at the focal length. The two-dimensional grating 7 is a circular two-dimensional discrete point structure array of 5 mm × 5 mm, with a horizontal and vertical grating period of 1 μm, a depth of 0.7 μm, a thickness of 1 mm, and a material of PDMS resin material. The industrial camera 8 is respectively arranged in two orthogonal side oblique directions of the two-dimensional grating 7. In the embodiment, the two orthogonal side oblique directions are parallel to the two grating directions in the horizontal plane, and are at an angle of 45° to the horizontal plane in the vertical direction.

[0020] See also Figure 2, the size of the two-dimensional grating 7 includes a transverse grating length 13 and a longitudinal grating length 14, both of which are 5 mm in this embodiment, and the main parameters of the two-dimensional grating include a transverse grating spacing 11 and a longitudinal grating spacing 12, both of which are 1 μm in this embodiment. The thickness 15 of the two-dimensional grating is 1 mm in the embodiment. After the parallel polychromatic light 4 is irradiated onto the two-dimensional grating plane, transverse diffraction light 5 and longitudinal diffraction light 6 are generated in the transverse and longitudinal lateral oblique directions. Among them, the processing methods of the two-dimensional grating include nanoimprint lithography technology, vibration imprint processing technology and vibration scratching processing technology.

[0021] See also Figure 1 , the working mode of the two-dimensional grating micro-deformation and micro-crack detection device is as follows:

[0022] 1. The point light source of complex light is emitted as incident light 2.

[0023] 2. The incident light 2 is refracted by a convex lens 3 placed at a vertical distance from 1 equal to the focal length, and the refracted light is parallel complex light 4.

[0024] 3. The parallel polychromatic light 4 is irradiated onto the surface of the two-dimensional grating 7, generating transverse diffraction light 5 and longitudinal diffraction light 6 in two orthogonal lateral oblique directions, namely, transverse and longitudinal directions.

[0025] 4. The transverse diffraction light 5 and the longitudinal diffraction light 6 are received by two industrial cameras, and after image processing, a longitudinal diffraction light pattern 9 and a transverse diffraction light pattern 10 are generated.

[0026] 5. The longitudinal diffraction light pattern 9 and the transverse diffraction light pattern 10 are solved to obtain the deformation caused by the two-dimensional grating, and the deformation morphology of the two-dimensional grating is generated after the solution, so as to use the relationship between the diffraction light and the deformation, and the diffraction light image received by the industrial camera 8 is processed to infer the deformation of the two-dimensional grating, so as to feedback the micro deformation and micro crack morphology of the mechanical surface. In this way, the measurement accuracy can be greatly improved, and the micro crack micro deformation detection from nanometer level to submicron level can be realized. The equipment is small in size and can adapt to the surface measurement of narrow space and tiny machinery or materials. There are no special requirements for the material surface and material, and it will not affect the material performance, nor will it damage the material or mechanical surface. Only light source, lens, two-dimensional grating, industrial camera are used, and the cost is low.

[0027] The image processing method is as follows: firstly, bilateral filtering is performed on the received diffraction light images in two directions, then image enhancement and region extraction are performed on the reference image and the diffraction light image, then the regions are integrated and edge extraction and discretization are performed, and finally, the extracted contour is solved to infer the strain distribution of the two-dimensional grating surface, thereby feeding back the micro-deformation and micro-cracks of the mechanical or material surface.

[0028] The two-dimensional grating surface is a two-dimensional grating structure array with a grating period of micrometer to submicrometer level and a depth of micrometer to submicrometer level, and its appearance is a discrete point structure array in the shape of circles, rectangular holes, columns and cones.

[0029] Wherein, the two-dimensional grating film is made of resin rubber material.

[0030] What is disclosed above is only one or more preferred embodiments of the present application, and cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of implementing the above embodiments and equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A two-dimensional grating type micro-deformation and micro-crack detection device, characterized in that: The invention comprises a polychromatic point light source, a convex lens, a two-dimensional grating, two industrial cameras and a shell. The shell is arranged outside the component to seal internal components. The convex lens is arranged below the polychromatic point light source to refract the incident light emitted by the point light source into parallel polychromatic light. The two-dimensional grating is arranged below the convex lens to diffract the parallel polychromatic light. The two industrial cameras are arranged in sequence at two orthogonal side oblique directions of the two-dimensional grating to receive diffracted light images.

2. The two-dimensional grating type micro-deformation and micro-crack detection device according to claim 1, characterized in that: The two-dimensional grating surface is a two-dimensional grating structure array with a grating period in the micron to submicron level and a depth in the micron to submicron level, and its appearance is a discrete point structure array in the shape of circular, rectangular holes, columns and cones.

3. The two-dimensional grating type micro-deformation and micro-crack detection device according to claim 2, characterized in that: The two-dimensional grating film is made of resin rubber material.

4. The two-dimensional grating type micro-deformation and micro-crack detection device according to claim 1, characterized in that: The complex color light point light source is a single point LED highlight light source, which is installed at the focus of the convex lens.

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