A method and system for detecting product surface defects

Abstract

A method and system for detecting product surface defects are disclosed. The system includes a steam accommodating space and an imaging detection device. The method includes selecting a development substance; volatilizing the development substance into steam; putting a product in the steam of the development substance to allow the steam of the development substance to nucleate and condense on the surface of the product; and detecting nucleating condensation differences of the development substance on the surface of the product, thus detecting surface defects. According to the method and the system, a principle that surface energy at a product surface defect part is different from surface energy at a defect-free part is utilized so that liquid drops / ice crystals formed at product surface defect parts and the defect-free parts are different in size and density when the steam of the development substance condenses on the surface of the product, and therefore the size, the shape and the position of a defect zone can be reflected so as to determine influences of the defect zone on product quality, low-cost detection for nanometer level defects can be achieved, and the system and the method are suitable for online continuous detection.

Description

technical field [0001] The invention relates to a defect detection technology, in particular to a method and system for detecting product surface defects. Background technique [0002] For products with high surface requirements (such as low-E coated glass, optical devices, some decorative coatings, high-definition TV screens, mobile phone screens, high-temperature superconducting tapes, etc.), surface defects are an important factor affecting the yield rate, and the products must pass through Only after passing the defect inspection can it be shipped to the user for use, and the semi-finished product must pass the defect inspection before entering the next process. In the production line of the coated glass industry, a high-speed line-scan camera + line-scan light source is generally used to obtain images of product surfaces and identify defects. When products with defects exceeding the threshold are found, the transmission system is automatically controlled to remove unqua...

AI Technical Summary

Problems solved by technology

[0003] The current online optical imaging inspection system can detect optically visible defects, but if the defects are invisible or optically indistinguishable, the current online optical inspection system cannot detect defects, so that defective products are finally passed test, send to user

In the use of users, defects will gradually appear, causing heavy losses to users

In the low-E coated glass industry, when the coated glass with invisible defects is delivered to the builder, after the builder installs it on the building, after a period of use, the invisible defects gradually develop into Visible defects that seriously impair function and aesthetics

As a result, the cost of replacement, compensation, and reputation loss far exceeds the cost of the glass. For all these losses, the builder will claim compensation from the coated glass manufacturer, and in severe cases, the coated glass manufacturer will be placed on the verge of bankruptcy.

Moreover, since these invisible defects have not been detected, it is unknown in which process and how they were generated, making it extremely difficult and costly to find the cause of such defects

In the production of high-temperature superconducting tapes, there will be some optically invisible defects in the polishing tape in the first process, such as transparent organic thin films of several nanometers, and these defects will appear in the subsequent high-temperature deposition process. This brings about two problems: (1) The defects that appear in the subsequent deposition process are likely to be mistaken for defects caused by the subsequent deposition process. All efforts to find the cause of the defects in the subsequent deposition process are Doing useless work delays problem solving and development progress

(2) The follow-up deposition process is expensive, and these defective polishing tapes should not enter the follow-up process, which also delays the delivery time

[0005] (1) A thin layer of transparent organic matter with a thickness of nanometers. When the film in the subsequent process is deposited on such a defect, it will sometimes break and appear, and sometimes it will not break or have tiny cracks. Although it is still optically invisible, but The adhesion of the defect is poor. In the subsequent use of the user, if it bears a certain external force, it will cause peeling and appear, causing the customer to claim

[0006] (2) Dense nano-scale particle groups, or located on the surface of the product or in the film embedded in the surface, such defects will cause cracks in the subsequent film, or cause the film to have poor resistance to external corrosion, because the corrosive medium is easy to move along the particles The interface with the thin film diffuses into the functional layer, such as the Ag layer of low-E coated glass

[0007] (3) Nano-scale roughness changes on the surface. Such defects will cause the texture of the high-temperature superconducting tape to deteriorate, the roughness of the film grown on it will also become poor, and the corrosion resistance of the film will decrease.

[0008] (4) There are a large number of nanoscale holes on the film. Such defects will obviously lead to a decrease in the diffusion resistance and corrosion resistance of the film, and eventually lead to film damage.

[0009] The wavelength of visible light is in the range of 0.4-0.8 microns, so these nano-scale defects cannot be directly observed by optical methods

Although high-resolution scanning electron microscopes and transmission electron microscopes can detect these defects, the cost is extremely high, and it is impossible for high-resolution scanning electron microscopes and transmission electron microscopes to be used in online systems

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