The film color difference sometimes occurs when the substrate is plated by the optical vacuum coating machine, which is not up to the standard of qualified products for the processing factory. Generally, the products with film color difference are all bad products. Therefore, the manufacturers are also very concerned about the occurrence of this situation. In the coating process of the vacuum coating machine, the film color difference of the substrate appears, so how to deal with it? There are generally two kinds of film color differences (excluding color spots) in the coated substrate. One is that the upper, middle and lower film colors of the whole cover are inconsistent, that is, the spectral test curves are different; Second, the color of single film is inconsistent.

Type 1: Inconsistent color of the upper, middle and lower films is called poor uniformity of the whole umbrella (cover), also called umbrella difference. The main reason is that the uniformity correction board (correction board) has problems.

The second type: umbrella sheet deformation. It is also one of the reasons for uneven film color, especially the umbrella sheet used for a long time, which was uniform in the past and gradually became uneven, and the deformation of the umbrella sheet may be the main reason.

Third, the inconsistency of film materials, especially the deviation of sublimed and semi-sublimed film materials, digging holes, etc., will also seriously affect the uniformity of the whole cover and single sheet. Especially when there are a lot of manual pre-melting, each person's operation methods are different, and the obtained material conditions will be different.

Solution to color difference of coating film in optical vacuum coating machine;

First, adjust the correction plates, and try to consider the balance compatibility of high and low refractive index films. If there are two evaporation sources, use their own correction plates independently under possible conditions to avoid interference.

Second: if conditions permit, use planetary clamp.

Third: umbrella shaping, which can be done by first processing an R basic die (selecting raw materials with higher strength), and shaping the umbrella on the basic die. In order to prevent and reduce the deformation of the umbrella sheet, the thickness and raw materials of the umbrella sheet should be properly selected when ordering the umbrella sheet.

Fourthly, strengthen the management of umbrella sheets, especially when placing them, to prevent them from being deformed due to improper placement.

Fifthly, improve the condition of film materials, especially when the electron gun evaporates sublimated and semi-sublimated materials, it is impossible to collapse the film materials and dig holes. Sixthly, the film material that can be automatically pre-melted should be automatically pre-melted as far as possible to reduce the influence of human factors.