Method and system for detecting nonuniformity of internal components of transparent glass by adopting OCT (optical coherence tomography)

Abstract

The invention discloses a method and a system for detecting nonuniformity of internal components of transparent glass by adopting OCT (Optical Coherence Tomography). The method comprises the following steps: S1, obtaining a three-dimensional image in the glass through the OCT; and S2, carrying out fault analysis on the three-dimensional image in the glass, and detecting defects in the glass according to refractive index change caused by non-uniform components. By adopting the technical scheme of the invention, the defects of uneven components, bubbles and microcracks in the glass can be accurately positioned and identified, and the quality control level of transparent glass products can be favorably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of glass detection, and in particular relates to a method and system for detecting non-uniform internal components of transparent glass by using OCT. Background Art

[0002] The uniformity of the internal composition of transparent glass is crucial in high-precision applications such as electronic product displays, optical components, and building materials. Minor inhomogeneities such as bubbles, microcracks, or uneven distribution of components may lead to stress concentration, reduced optical performance, or defects in subsequent processing. Traditional inspection methods have difficulty accurately identifying these defects in large areas of transparent glass, especially non-surface tiny internal defects. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method and system for detecting the uneven composition inside transparent glass by using OCT.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] A method for detecting uneven internal components of transparent glass using OCT, comprising:

[0006] Step S1, obtaining a three-dimensional image of the interior of the glass through OCT;

[0007] Step S2: Perform a tomographic analysis on the three-dimensional image inside the glass, and detect defects inside the glass based on the change in refractive index caused by uneven composition.

[0008] Preferably, step S1 comprises:

[0009] The 2D scanning system moves the light beam in the X and Y directions to scan the large area of ​​the glass horizontally;

[0010] OCT can be used to perform layered imaging at different depths inside the glass, and combined with the lateral scanning data, a three-dimensional image of the interior of the glass can be obtained.

[0011] Preferably, the defects inside the glass in step S2 include: bubbles, impurities, uneven distribution of components and microcracks.

[0012] The present invention also provides a system for detecting the inhomogeneity of the internal components of transparent glass using OCT, comprising: a low-coherence light source, an interferometer, a data processing system and a three-dimensional scanning system; wherein:

[0013] The three-dimensional scanning system, low-coherence light source and interferometer obtain a three-dimensional image of the inside of the glass through OCT; the data processing system performs tomographic analysis on the three-dimensional image of the inside of the glass and detects defects inside the glass based on changes in refractive index caused by uneven composition.

[0014] Preferably, the light beam is moved in the X and Y directions by a two-dimensional scanning system to perform lateral scanning on a large area of ​​the glass; the interior of the glass can be layered imaged at different depths based on OCT technology using a low-coherence light source and an interferometer, and a three-dimensional image of the interior of the glass can be obtained by combining the lateral scanning data.

[0015] Preferably, the defects inside the glass include: bubbles, impurities, uneven distribution of components and microcracks.

[0016] The present invention adopts OCT technology to detect the uneven internal composition of large-area transparent glass. Through its high-resolution three-dimensional imaging capability, combined with intelligent analysis algorithms, it can accurately locate and identify tiny defects such as uneven composition, bubbles, cracks, etc. inside the glass, which helps to improve the quality control level of transparent glass products. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0018] Figure 1 This is a flow chart of a method for detecting uneven internal components of transparent glass using OCT according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of 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.

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Embodiment 1:

[0022] like Figure 1 As shown, an embodiment of the present invention provides a method for detecting uneven internal components of transparent glass using OCT, comprising:

[0023] Step S1, obtaining a three-dimensional image of the interior of the glass through OCT;

[0024] Step S2: Perform a tomographic analysis on the three-dimensional image inside the glass, extract tiny signal changes based on the refractive index changes caused by uneven composition, and detect defects inside the glass.

[0025] Preferably, step S1 comprises:

[0026] The 2D scanning system moves the light beam in the X and Y directions to scan the large area of ​​the glass horizontally;

[0027] OCT can be used to perform layered imaging at different depths inside the glass, and combined with the lateral scanning data, a three-dimensional image of the interior of the glass can be obtained.

[0028] Preferably, the defects inside the glass in step S2 include: bubbles, impurities, uneven distribution of components and microcracks. There are obvious strong reflection points or abnormal areas in the OCT image, and the contour features are relatively obvious. Therefore, the refractive index information of the abnormal area is first extracted, and then the judgment is made based on the analysis of the Fourier change data of the refractive index data information and the contour information.

[0029] Bubbles and impurities:

[0030] The refractive index changes of bubbles are mostly: transparent, large deviation, obvious mutation, and the turning point of the mutation is more prominent. The curve after Fourier transformation has obvious peaks (the light enters the gas in the bubble from the vitreous body, resulting in a large refractive index change, and then penetrates the bubble into the vitreous body, and the refractive index undergoes a second mutation). In addition, the image contours of the bubbles are relatively smooth, all spherical or ellipsoidal, with clear edges and mostly dark black lines.

[0031] Impurities and stones: The refractive index changes of light are mostly: not transparent, no signal of refractive index change can be detected, and no data is produced after Fourier transform; in addition, the image contours of impurities and stones are relatively irregular in shape, and the edges of the contours are also relatively complex, but there are basically no spherical or ellipsoidal contours.

[0032] Uneven distribution of components: The refractive index changes relatively slowly, and the signal receiving intensity after transmission is high. The curve after Fourier transformation fluctuates significantly, but the change process is relatively smooth. There is no obvious outline in the image.

[0033] Microcracks: Similar to the light transmission of bubbles, they can be transmitted, have large deviations, have obvious mutations, and the turning point of the mutation is more prominent. The curve after Fourier transformation has obvious peaks, but the difference is that the peaks are more concentrated. In addition, the outline of the image is mostly spike-shaped or linear.

[0034] For different glass defects, the propagation phase change of light can be described by the following formulas:

[0035] 1. Normal and internally uneven glass:

[0036]

[0037] Among them, λ is the wavelength of light, n0 is the refractive index of glass, and z is the distance along the direction of light propagation. As long as there is an area with inhomogeneous internal components, the refractive index will change accordingly, but it is generally relatively gentle, and the Fourier signal is mainly concentrated in the low-frequency area.

[0038] 2. There are bubbles:

[0039]

[0040] Among them, Δn(z) represents the local refractive index change caused by the bubble, which usually changes more dramatically at the edge of the bubble.

[0041] 3. Presence of stones:

[0042]

[0043] Among them, Δn s (z) represents the local refractive index change caused by the stone, which is usually more drastic in the stone area.

[0044] 4. Presence of microcracks:

[0045]

[0046] Among them, Δn c (z) represents the local refractive index change caused by the presence of microcracks. Usually, the change is more obvious in the area where the microcracks are located, but the range is small and the distribution is more complex.

[0047] For signal processing, Fourier transform can be used to convert the signal from the spatial domain to the frequency domain. In the frequency domain, bubbles, stones and microcracks usually appear as different frequency components. By analyzing these frequency components, different types of defects can be distinguished. The frequency range of the signal after Fourier transform is shown in Table 1:

[0048] Table 1

[0049] Defect Type Main spatial scale Frequency range Frequency domain characteristics Normal glass Homogeneous medium Low Frequency The signal is smooth, without obvious high-frequency fluctuations Uneven internal composition Inhomogeneous media IF The signal is relatively smooth, but there are obvious fluctuations bubble Mesoscale defects high frequency The low frequency changes little, and the high frequency is more obvious Impurity stones Large scale defects Low Frequency Low frequency changes or no information Micro cracks Small scale defects High to mid-range Complex high and low frequencies, sharp signals

[0050] The embodiments of the present invention have the following technical effects:

[0051] 1. Non-destructive testing: OCT is a non-contact imaging technology that does not require destroying or changing the structure of the glass and is suitable for transparent material testing with high precision requirements.

[0052] 2. High resolution: OCT has a micron-level longitudinal resolution, which can effectively identify tiny internal component inhomogeneities or defects.

[0053] 3. Large area coverage: Combined with the scanning system and data processing algorithm, large areas of glass can be fully covered within a reasonable time.

[0054] 4. Real-time detection: With high detection speed, it can realize real-time online detection on the production line and effectively improve production efficiency.

[0055] Embodiment 2:

[0056] An embodiment of the present invention further provides a system for detecting non-uniform components inside transparent glass using OCT, comprising: a low-coherence light source, an interferometer, a data processing system and a three-dimensional scanning system.

[0057] Low-coherence light sources use broadband light sources, such as superluminescent diodes (SLDs), to provide low-coherence light beams. The wavelength range can be selected from the near-infrared band (such as 800nm ​​or 1300nm), which is suitable for imaging transparent materials. The interferometer is based on the Michelson interferometer structure. The light beam is divided into a reference arm and a sample arm. The light beam from the sample arm illuminates the glass to be tested, and the reference arm interferes with the reflected light from the sample. The data processing system processes the signal through fast Fourier transform (FFT) based on the interference signal to generate tomographic images of different depths. The three-dimensional scanning system scans a large area of ​​glass point by point through two-dimensional optical scanning (such as using a scanning galvanometer) to obtain a three-dimensional structure diagram of the entire glass.

[0058] Furthermore, the three-dimensional scanning system, low-coherence light source and interferometer obtain a three-dimensional image of the inside of the glass through OCT; the data processing system performs tomographic analysis on the three-dimensional image of the inside of the glass, extracts tiny signal changes based on the refractive index changes caused by uneven composition, and detects defects inside the glass.

[0059] Furthermore, the light beam is moved in the X and Y directions through a two-dimensional scanning system to perform lateral scanning on a large area of ​​the glass. Based on OCT technology, layered imaging of the interior of the glass at different depths can be performed using a low-coherence light source and an interferometer. Combined with the lateral scanning data, a three-dimensional image of the interior of the glass can be obtained.

[0060] Furthermore, defects inside the glass include: bubbles, impurities, uneven distribution of components and microcracks.

[0061] Bubbles and impurities: They form strong reflection points or local abnormal areas in the OCT image, which are clearly distinguished from the uniform areas of the glass.

[0062] Uneven distribution of components: Due to changes in the refractive index, the signal intensity and phase of the OCT image will produce local differences. After analysis by the feature extraction algorithm, areas with uneven components can be identified.

[0063] Microcracks: Microcracks can lead to enhanced light scattering, forming a unique linear signal structure. Crack areas can be automatically detected and marked through pattern recognition technology.

[0064] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for detecting the uneven composition of transparent glass using OCT, characterized in that: include: Step S1, obtaining a three-dimensional image of the interior of the glass through OCT; Step S2: Perform a tomographic analysis on the three-dimensional image inside the glass, and detect defects inside the glass based on the change in refractive index caused by uneven composition.

2. The method for detecting the inhomogeneity of the internal composition of transparent glass using OCT as claimed in claim 1, characterized in that: Step S1 includes: The 2D scanning system moves the light beam in the X and Y directions to scan the large area of ​​the glass horizontally; OCT can be used to perform layered imaging at different depths inside the glass, and combined with the lateral scanning data, a three-dimensional image of the interior of the glass can be obtained.

3. The method for detecting the non-uniform composition of the interior of transparent glass using OCT as claimed in claim 2, characterized in that: The defects inside the glass in step S2 include: bubbles, impurities, uneven distribution of components and microcracks.

4. A system for detecting uneven internal components of transparent glass using OCT, characterized in that: include: Low coherence light source, interferometer, data processing system and three-dimensional scanning system; among them, The three-dimensional scanning system, low-coherence light source and interferometer obtain a three-dimensional image of the inside of the glass through OCT; the data processing system performs tomographic analysis on the three-dimensional image of the inside of the glass and detects defects inside the glass based on changes in refractive index caused by uneven composition.

5. The system for detecting non-uniform composition inside transparent glass using OCT as claimed in claim 4, characterized in that: The two-dimensional scanning system moves the light beam in the X and Y directions to perform lateral scanning on a large area of ​​the glass. The low-coherence light source and interferometer based on OCT technology can perform layered imaging at different depths inside the glass, and combined with the lateral scanning data, a three-dimensional image of the interior of the glass can be obtained.

6. The system for detecting non-uniform composition inside transparent glass using OCT as claimed in claim 5, characterized in that: Defects inside the glass include bubbles, impurities, uneven distribution of components and microcracks.

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