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What to do when the film color is different?

Update:20-10-2021
Summary: There are two kinds of film color differences (not including stains). One is that the upper, middle...
There are two kinds of film color differences (not including stains). One is that the upper, middle, and lower film colors of the entire mask are inconsistent, that is, the spectroscopic test curves are different; the second is that the color of the single film is inconsistent.
1. The inconsistency of the upper, middle and lower film colors is called poor uniformity of the entire umbrella (cover), also called umbrella difference. The main reason is that there is a problem with the uniformity correction board (correction board).
2. Umbrella pieces are deformed. It is also one of the reasons for the uneven film color, especially the umbrella pieces that have been used for a long time, which used to be uniform, but gradually become uneven, and the deformation of the umbrella pieces may be the main reason.
3. The inconsistency of the film material, especially the sublimation and semi-sublimation film material is deflected, digging, etc. will also seriously affect the uniformity of the whole cover and single chip. Especially when there is a large amount of manual pre-melting, the operation methods of each person are different, and the material conditions obtained will also be different.
Improvement ideas: Fully use the function of the correction board.
Improve strategy:
Adjust the correction plate, try to consider the balance and compatibility of high and low refractive index film materials. If there are two evaporation sources, use their own correction plates independently if possible to avoid interference.
Conditions permit, using planetary fixtures.
Umbrella shaping, you can first process an R base mold (choose high-strength raw materials) to shape the umbrella piece on the base mold. In order to prevent the deformation of umbrella pieces, the thickness and raw materials of umbrella pieces should be selected appropriately when ordering umbrella pieces.
Strengthen the management of umbrella pieces, especially the management during placement, to prevent deformation due to improper placement.
Improve the condition of the film material, especially when the electron gun evaporates sublimation and semi-sublimation materials, the film material cannot be collapsed and pits are not allowed.
The film material that can be automatically pre-melted should be automatically pre-melted as much as possible to reduce the influence of human factors.
The correction plate is very effective in correcting the physical film thickness, but it is incapable of correcting the refractive index. Therefore, it is very difficult to completely rely on the correction plate to solve the spectral uniformity.
If one correction board needs to correspond to two electron guns (evaporation sources) and a variety of film materials, there will be greater difficulties.
The reasons for the uneven color of the single film:
It is mainly due to the serious unevenness of the substrate, which is quite different from the curvature of the umbrella, and the evaporation angle formed by the upper or lower normal line of the substrate and the evaporation source is quite different. This results in a large difference in the conditions for receiving the film material on each part of a lens, and a large difference in the thickness of the formed film.
In addition, the lens is blocked by the edge of the lens ring (disc), the lens ring (disc) is dirty and contaminates the lens during evaporation, etc., which can also cause film color differences.
Improvement ideas: improve the evaporation angle of the edge of the lens.
Improve strategy:
Conditions permit, use planetary fixtures;
Choose a machine with a flat umbrella (large R);
According to the distribution of the umbrella holes and the shape of the substrate, a special zigzag correction board is made.
If possible, moving the evaporation source to the middle of the vacuum chamber can also improve the uniformity of the monolithic film color.
Improve the lens ring (disc) to prevent blocking.
Note that the corresponding part of the rotating umbrella frame partially blocks the edge lens
Clean the lens ring (disc)
Improve the evaporation of the film material.
Founded in 2007 as previous name Huahong Vacuum Technology,is professional China Optical film coating machines suppliers and Optical film coating machines suppliers ,including but not limited to Sputtering Systems, Optical Coating Units, Batch Metallizers, Physical Vapor Deposition (PVD) Systems, Hard and Wear Resistant Vacuum Coating Deposition Equipment, Glass, PE, PC Substrate Coaters, Roll-to-Roll Machines for coating flexible substrates. The machines are used for a wide range of applications described below (but not limited to) Automotive, Decorative, Hard coatings, Tool & Metal Cutting coatings, and thin film Coating applications for industrial and Laboratories including Universities.Danko Vacuum Technology Company Ltd is committed to expand our market boundaries by providing high-quality, high-performance and wholesale Optical film coating machine prices. Our Company is highly focus on after-sales service in Domestic and International markets, providing accurate part processing plans and professional solutions to meet customers need.

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