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A detection method for smooth surface defects

A detection method and smooth surface technology, which are applied in optical testing of flaws/defects, measuring devices, and material analysis by optical means, etc., can solve the problems of complex device structure, low detection accuracy and high cost

Active Publication Date: 2020-04-03
EDINBURGH NANJING OPTO ELECTRONICS EQUIP CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, although there are related reports about surface defect detection devices, they have not been widely promoted due to the complex structure of the device, high requirements for parts such as cameras, high cost, poor adaptability, and low detection accuracy.

Method used

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  • A detection method for smooth surface defects
  • A detection method for smooth surface defects
  • A detection method for smooth surface defects

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] A detection method for smooth surface defects, bright field irradiation is carried out on the surface of the component to be tested; the bright field image of the surface of the component to be tested is obtained by using a camera, and the spots on the bright field image are defects on the surface of the component to be tested; by measuring the size of the spot Get the level of the defect.

[0053] The above method is applicable to the detection of spherical and aspheric smooth surface defects, and the smooth surface to be tested can be transparent or opaque.

[0054] For small-sized lenses, such as lenses with a diameter of less than 1 inch, especially mobile phone camera lenses with a diameter of less than 5 mm, when the image resolution of the camera can reach the size of surface defects (scratches and spots, etc.), direct physical Size measurement becomes possible. This embodiment adopts the detection method of double-lens bright field illumination, see figure 1 ,...

Embodiment 2

[0056] A method for detecting defects on a smooth surface. Partial dark field irradiation is performed on the surface of a component to be tested; in the local dark field, the boundary line between the dark field and the bright field passes through the center of the component to be tested or the boundary line between the dark field and the bright field is a straight line, And the area of ​​the dark field is not smaller than the area of ​​the bright field. Use the camera to obtain the image of the dark field part of the surface of the component to be tested, and obtain the dark field image of the entire surface of the component to be tested by rotating the component to be tested. The spots on the dark field image are Defects on the surface of the component to be tested, the grade of the defect is obtained by measuring the size of the spot.

[0057] The above method is applicable to the detection of spherical and aspheric smooth surface defects, and the smooth surface to be teste...

Embodiment 3

[0061] It is basically the same as Embodiment 2, the difference is that in this embodiment, local dark field illumination is obtained by horizontal light side illumination: as Figure 4 As shown, the detected lens 2 is illuminated by the horizontal light 8 on its side. When the front-facing camera 3 takes a picture of the detected lens 2, the light-receiving surface of the detected lens 2 will cause the entire picture to appear The effect of "yin and yang faces", the light-facing surface presents a bright field effect in the image (bright field 11 formed by the light-facing surface), while the backlight surface presents a dark field effect in the image (dark field 10 formed by the backlight surface) , the inspected lens 2 is rotated 360 degrees, thereby obtaining the defect image of the entire inspected lens 2 upper surface, and realizing the defect classification of the entire inspected lens 2 upper surface. Obtain the defect level of the lower surface simultaneously or succe...

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Abstract

The invention discloses a detection method for smooth surface defects. Bright field or local dark field irradiation is carried out on a surface of a to-be-detected element. When the bright field irradiation is carried out, a bright field image of the surface of the to-be-detected element is obtained through utilization of a camera. When the local dark field irradiation is carried out, an image ofa dark field part of the surface of the to-be-detected element is obtained through utilization of the camera. Dark field images of the whole surface of the to-be-detected element are obtained throughrotation of the to-be-detected element. Spots on the bright field image or the dark field images are defects on the surface of the to-be-detected element. Levels of the defects are obtained through measurement of sizes of the spots. The method is applicable to detection of spherical, aspherical, transparent and nontransparent smooth surface detects. The method is good in adaptability. A detectiondevice is simple in structure. A requirement for a pixel of the camera is low. Cost is low. Detection precision is high. Upper and lower surfaces of the to-be-detected element also can be detected atthe same time. Detection efficiency is high.

Description

technical field [0001] The invention relates to a detection method for smooth surface defects, which belongs to the field of surface detection. Background technique [0002] Smooth surfaces, especially optical-grade smooth surfaces, such as glass, plastic, silicon, germanium, zinc selenide, zinc sulfide, gemstones, metals and other optical-grade surfaces with relatively high requirements, are extremely tolerant to defects such as surface scratches and spots Low, the width of some scratches is required to be as small as the order of microns, and the size of some spots is also required to be as small as 2.5 microns. [0003] However, due to the limitations of modern processing technology, various defects such as pitting, scratches, open air bubbles and broken edges will inevitably be left on the surface of smooth components during processing, which will affect the quality of use. [0004] Traditionally, defects on component surfaces are detected manually. Although there are ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N21/95G01N21/958G01N21/88
Inventor 王善忠黄胜弟
Owner EDINBURGH NANJING OPTO ELECTRONICS EQUIP CO LTD