A microscopic optical internal microscopic defect detection device and detection method thereof

Abstract

The present application provides a microscopic internal microscopic defect detection device and a detection method thereof, a microscope objective lens with a refractive index medium as the object medium, the refractive index medium is in liquid form, and its refractive index is precisely matched with that of a sample to be detected, and the object surface of the microscope objective lens is immersed in the refractive index matching liquid. During detection, the object surface of the microscope objective lens can be moved relative to the sample to be detected so that the microscope objective lens can be focused to different heights inside the sample to be detected, thereby achieving full detection of internal defects of the component. The present invention can solve the problem that existing detection methods cannot perform high-precision detection of the interior of the component, and meet the needs of high-precision body defect detection in the industrial field.

Description

Technical Field

[0001] The present invention relates to the field of microscopic detection technology, and in particular to a microscopic optical internal microscopic defect detection device and a detection method thereof. Background Art

[0002] Currently, most optical systems for industrial microscopic inspection use microscopic systems, which use the high resolution of microscope objective lenses to achieve high-precision inspection of microscopic defects or features of products.

[0003] However, the higher the resolution of the microscope, the larger the NA must be, so the depth of field is smaller, and there is a contradiction between the two indicators of resolution and depth of field. Therefore, industrial microscopic inspection equipment can only detect the surface of the component to be inspected, but cannot detect the internal defects of the component.

[0004] In the field of high-end precision manufacturing, the detection of subtle defects inside components is crucial, and the industry has an urgent need for this. However, on the other hand, the market still lacks effective detection equipment, so there is an urgent need to fill the technology gap. Summary of the invention

[0005] The present invention aims to solve the problem that existing detection methods cannot perform high-precision detection of the interior of components, and to provide an optical internal microscopic defect detection device that can detect microscopic defects inside (transparent) components with high precision, which can meet the needs of high-precision body defect detection in the industrial field.

[0006] This application adopts the following technical solutions: A microscopic internal microscopic defect detection device comprises a microscope objective lens, the object surface of which is immersed in a refractive index matching liquid, the refractive index of which matches that of a sample to be detected, and the object surface of which can move relative to the sample to be detected so that the microscope objective lens can be focused to different heights inside the sample to be detected.

[0007] Preferably, the sample to be detected and the object surface of the microscope objective lens are both immersed in the refractive index matching liquid, and the sample to be detected or the microscope objective lens can move in the refractive index matching liquid.

[0008] Preferably, the sample to be detected is arranged outside the refractive index matching liquid, and a window piece is arranged on the refractive index matching liquid between the object plane of the microscope objective lens and the sample to be detected. The position between the window piece and the sample to be detected is fixed, and the microscope objective lens can move in the refractive index matching liquid.

[0009] Preferably, the entire object-side refractive index of the microscope objective is equal to the refractive index of the sample to be detected.

[0010] Preferably, the refractive index matching method is as follows: The refractive index matching medium is set to a constant refractive index value; During testing, the intersection of the design value and the refractive index curve of the sample to be tested is the working wavelength; Customized refractive index matching liquid to meet the designed refractive index value at the working wavelength.

[0011] Preferably, the refractive index matching method is as follows: The refractive index matching medium is set to a known refractive index matching liquid; During detection, the intersection of the refractive index matching liquid and the refractive index curve of the sample to be detected is the working wavelength.

[0012] Another object of the present application is to provide a microscopic optical automatic detection method, which uses the above-mentioned microscopic optical automatic detection device and includes the following steps: Obtaining a refractive index matching liquid that matches the refractive index of the sample to be measured; The object plane of the microscope objective is immersed in the refractive index matching liquid; Move the relative distance between the object plane of the microscope objective and the sample to be tested to scan the entire interior of the sample to be tested.

[0013] Preferably, the relative distance between the object plane of the microscope objective lens and the sample to be detected is moved, specifically comprising: The initial working distance between the microscope objective lens and the sample to be detected enables the microscope objective lens to focus on the upper surface of the sample to be detected, and then the microscope objective lens moves downward to scan the entire interior of the sample to be detected.

[0014] Preferably, the relative distance between the object plane of the microscope objective lens and the sample to be detected is moved, specifically comprising: The initial working distance between the microscope objective lens and the sample to be detected enables the microscope objective lens to focus on the lower surface of the sample to be detected, and then the microscope objective lens moves upward to scan the entire interior of the sample to be detected.

[0015] Preferably, the relative distance between the object plane of the microscope objective lens and the sample to be detected is moved, specifically comprising: The microscope objective remains stationary, and the sample to be tested moves up and down to scan the entire interior of the sample. Compared with the prior art, the present invention has the following beneficial effects: The present application provides a microscopic internal microscopic defect detection device and a detection method thereof, a microscope objective lens with a refractive index medium as the object medium, the refractive index medium is in liquid form, and its refractive index is precisely matched with that of a sample to be detected, and the object surface of the microscope objective lens is immersed in the refractive index matching liquid. During detection, the object surface of the microscope objective lens can be moved relative to the sample to be detected so that the microscope objective lens can be focused to different heights inside the sample to be detected, thereby achieving full detection of internal defects of the component. The present invention can solve the problem that existing detection methods cannot perform high-precision detection of the interior of the component, and meet the needs of high-precision body defect detection in the industrial field. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of an existing microscopic detection device; Figure 2 This is a schematic diagram of the structure of Example 1 of the present application; Figure 3 This is a schematic diagram of the structure of Example 2 of the present application; Figure 4 This is a schematic diagram of the refractive index matching method of Example 3 of the present application; Figure 5 This is a schematic diagram of the refractive index matching method of Example 4 of the present application. DETAILED DESCRIPTION

[0017] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] A microscopic internal defect detection device comprises a microscope objective lens 1, the object surface of the microscope objective lens 1 is immersed in a refractive index matching liquid 4, the refractive index of the refractive index matching liquid 4 matches that of a sample to be detected 2, and the object surface of the microscope objective lens 1 can move relative to the sample to be detected 2 so that the microscope objective lens 1 can be focused to different heights inside the sample to be detected 2.

[0019] A microscopic optical automatic detection method, applied to the above-mentioned microscopic optical automatic detection device, comprises the following steps: S1, obtaining a refractive index matching liquid 4 that matches the refractive index of the sample 2 to be tested; S2, immersing the object surface of the microscope objective lens 1 in the refractive index matching liquid 4; S3, moving the relative distance between the object plane of the microscope objective lens 1 and the sample to be detected 2, and scanning the entire interior of the sample to be detected 1.

[0020] The present application designs a microscope objective lens with a refractive index medium as the object medium. The refractive index medium is in liquid form, and its refractive index accurately matches that of the sample to be tested. During detection, the objective lens moves up and down in the medium, so that the object plane can be focused to different heights inside the sample, thereby achieving full detection of defects inside the component. The present invention can solve the problem that existing detection methods cannot perform high-precision detection of the inside of the component, and meet the needs of high-precision body defect detection in the industrial field.

[0021] See also Figure 1-3 , Figure 1 It is the structure of conventional microscopic detection equipment; Figure 2 is the detection structure of the detection device of embodiment 1 of the present invention; Figure 3This is the detection structure of the detection device of Example 2 of the present invention; in the figure, 1-microscope objective lens, 2-sample to be detected, 3-air, 4-refractive index matching liquid, 5-window plate; the black and white lines in the sample are schematic diagrams of internal defects.

[0022] By the attached Figure 1 It can be seen that conventional optical microscopic detection equipment can only detect the upper surface of the sample, but cannot deeply detect the defects inside the sample. The present invention can achieve complete optical microscopic detection of the inside of the sample by designing a specially designed immersion objective lens.

[0023] As a preferred embodiment of this application, Figure 2 In the embodiment 1 shown, the sample to be tested and the object surface of the microscope objective lens are both immersed in the refractive index matching liquid, and the sample to be tested or the microscope objective lens can move in the refractive index matching liquid. During the test, the sample and the end surface of the objective lens are both immersed in the refractive index matching liquid. There is only one medium, the refractive index matching liquid, between the sample and the objective lens. The starting working distance between the objective lens and the sample allows the objective lens to focus on the upper surface of the sample, and then the objective lens moves downward to scan the entire sample interior; the starting working distance between the objective lens and the sample allows the objective lens to focus on the lower surface of the sample, and then the objective lens moves upward to scan the entire sample interior; the objective lens can also be kept stationary, and the sample moves up and down to scan the entire sample interior. When the objective lens is designed, the refractive index of the entire object side is corrected to be equal to the refractive index of the sample, so that the entire sample testing process will not be limited by the depth of field of the microscope objective lens, but only by the working distance of the objective lens. During the test process, any slight defects on the surface and inside of the sample will form strong scattered light to be detected, while the defect-free area will transmit light and appear as a dark background.

[0024] As another preferred embodiment of the present application, Figure 3 In the embodiment 2 shown, the sample to be detected is arranged outside the refractive index matching liquid, and a window piece is arranged on the refractive index matching liquid between the object plane of the microscope objective lens and the sample to be detected. The position between the window piece and the sample to be detected is fixed, and the microscope objective lens can move in the refractive index matching liquid. During detection, the sample is placed in the air, and the objective lens is placed in the refractive index matching liquid. There are three media between the objective lens and the sample, namely, the refractive index matching liquid, the window piece, and the air. During measurement, the thickness of the window piece and the thickness of the air are fixed, and the objective lens moves up and down in the refractive index matching liquid to scan the entire interior of the sample.

[0025] For the test piece with curvature on the surface, such as 2.5D glass, the solution of Example 1 can be used to avoid the influence of surface optical focal length on high-precision imaging; for the test piece with a precisely flat surface, the solution of Example 2 can be used to make the system deployment and detection process more flexible.

[0026] The objective lens structure shown in the figure is for illustration only. In fact, the object media of the three objective lenses are different, so the internal structures are also different. Figure 1 The object medium of the objective lens is air. Figure 2 The object side medium of the objective lens is a refractive index matching liquid. Figure 3 The objective medium of the objective lens is refractive index matching liquid, window plate, and air. Different corrections need to be designed for the three objective lenses.

[0027] On the other hand, considering that it is difficult for the refractive index matching liquid and the sample to meet the refractive index matching in the entire visible light band, the system adopts a single-wavelength operation mode, so that the refractive index matching requirement is reduced from the refractive index curve matching to the single-wavelength refractive index value matching.

[0028] The refractive index matching design of the objective lens can be implemented in two ways: (1) Example 3 Figure 4 As shown in the figure, the objective lens sets the refractive index matching medium to a constant refractive index value (a horizontal line parallel to the wavelength axis) on the object side. During the test, the intersection of the design value and the refractive index curve of the sample is the working wavelength. Then the refractive index matching liquid is customized to meet the design refractive index value at the working wavelength. The advantage of this is that it does not require a refractive index matching liquid of a specific model and manufacturer, but only requires the manufacturer to be able to mix the refractive index value of the specified wavelength; the disadvantage is that a matching liquid must be customized for each sample.

[0029] (2) Example 4 Figure 5 As shown in the figure, the refractive index matching medium is set as a known stable commercial refractive index matching liquid material on the object side of the objective lens. During the test, the intersection of the refractive index matching liquid and the refractive index curve of the sample is the working wavelength. The advantage of this is that the real medium corresponds and there is no need to customize the refractive index matching liquid; the disadvantage is that the objective lens is bound to the manufacturer and model of the refractive index matching liquid, and only the specified refractive index matching liquid can be used.

[0030] The detection system works in single wavelength mode, so the illumination and detection also need to work in single wavelength mode. There are two specific implementation methods: Use single wavelength illumination, such as laser illumination; Use white light for illumination and set narrow-band filters on the detection light path to avoid noise caused by other wavelengths of light.

[0031] In this way, a closed loop is formed in terms of detection method, objective lens design, lighting, detection, etc., so that the detection equipment can achieve the function of completely scanning the sample.

[0032] The objective lens is somewhat similar to an oil immersion objective lens (liquid immersion objective lens) in terms of design, but it has at least the following differences from the oil immersion objective lens: 1. The traditional oil immersion objective lens uses the high refractive index of the medium to obtain a larger NA, with the purpose of further increasing the resolution of the objective lens. The objective lens involved in the present invention uses the characteristics that the medium can match the refractive index of the element to be measured and the objective lens can move freely in the medium, so there are differences in the characteristics and functions used.

[0033] 2. Traditional oil immersion objective lenses are mostly used for high-power or even ultra-high-power objective lenses (for example, above 60x). However, the detection conditions targeted by the present invention require a certain working distance, so they are more often used for objective lenses with lower magnifications (for example, below 40x); 3. There is only one medium between the conventional oil-immersion objective lens and the object surface, usually deionized water or various refractive index matching liquids. However, in addition to the refractive index matching liquid, glass, air, etc. may also exist between the objective lens and the object surface involved in the present invention.

[0034] The present application provides a microscopic internal microscopic defect detection device and a detection method thereof, a microscope objective lens with a refractive index medium as the object medium, the refractive index medium is in liquid form, and its refractive index is precisely matched with that of a sample to be detected, and the object surface of the microscope objective lens is immersed in the refractive index matching liquid. During detection, the object surface of the microscope objective lens can be moved relative to the sample to be detected so that the microscope objective lens can be focused to different heights inside the sample to be detected, thereby achieving full detection of internal defects of the component. The present invention can solve the problem that existing detection methods cannot perform high-precision detection of the interior of the component, and meet the needs of high-precision body defect detection in the industrial field.

[0035] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A microscopic optical internal microscopic defect detection device, characterized in that: The object surface of the microscope objective lens is immersed in a refractive index matching liquid, the refractive index of the refractive index matching liquid matches that of the sample to be tested, and the object surface of the microscope objective lens can move relative to the sample to be tested so that the microscope objective lens can be focused to different heights inside the sample to be tested.

2. The microscopic optical internal microscopic defect detection device according to claim 1, characterized in that: The sample to be detected and the object surface of the microscope objective are both immersed in the refractive index matching liquid, and the sample to be detected or the microscope objective can move in the refractive index matching liquid.

3. The microscopic optical internal microscopic defect detection device according to claim 1, characterized in that: The sample to be detected is arranged outside the refractive index matching liquid, and a window piece is arranged on the refractive index matching liquid between the object plane of the microscope objective lens and the sample to be detected. The position between the window piece and the sample to be detected is fixed, and the microscope objective lens can move in the refractive index matching liquid.

4. The microscopic optical internal microscopic defect detection device according to claim 1, characterized in that: The refractive index of the entire object side of the microscope objective is equal to the refractive index of the sample to be detected.

5. The microscopic optical internal microscopic defect detection device according to claim 1, characterized in that: The refractive index matching method is as follows: The refractive index matching medium is set to a constant refractive index value; During testing, the intersection of the design value and the refractive index curve of the sample to be tested is the working wavelength; Customized refractive index matching liquid to meet the designed refractive index value at the working wavelength.

6. The microscopic optical internal microscopic defect detection device according to claim 1, characterized in that: The refractive index matching method is as follows: The refractive index matching medium is set to a known refractive index matching liquid; During detection, the intersection of the refractive index matching liquid and the refractive index curve of the sample to be detected is the working wavelength.

7. A microscopic optical automatic detection method, using a microscopic optical automatic detection device according to any one of claims 1 to 6, characterized in that: The following steps are involved: Obtaining a refractive index matching liquid that matches the refractive index of the sample to be measured; The object plane of the microscope objective is immersed in the refractive index matching liquid; Move the relative distance between the object plane of the microscope objective and the sample to be tested to scan the entire interior of the sample to be tested.

8. The microscopic optical automatic detection method according to claim 7, characterized in that: Move the relative distance between the object plane of the microscope objective and the sample to be detected, including: The initial working distance between the microscope objective lens and the sample to be detected enables the microscope objective lens to focus on the upper surface of the sample to be detected, and then the microscope objective lens moves downward to scan the entire interior of the sample to be detected.

9. The microscopic optical automatic detection method according to claim 7, characterized in that: Move the relative distance between the object plane of the microscope objective and the sample to be detected, including: The initial working distance between the microscope objective lens and the sample to be detected enables the microscope objective lens to focus on the lower surface of the sample to be detected, and then the microscope objective lens moves upward to scan the entire interior of the sample to be detected.

10. The microscopic optical automatic detection method according to claim 7, characterized in that: The relative distance between the object plane of the microscope objective and the sample to be detected is moved, specifically including: the microscope objective is stationary, the sample to be detected is moved up and down, and the entire interior of the sample is scanned.

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