Coated glass (filter) common problem - falling film

Aug. 14, 2019


Film dropping: Optical Coating Supplier shares that the phenomenon of local film dropping or peeling on the surface of coated glass film layer. The main manifestations are local enhancement of light transmittance or complete shedding of membrane layer. We have strict standard control over the film falling phenomenon in the production process. Generally speaking, it is not allowed for the diameter of the film falling site to be larger than 2.5mm.

Causes: there are many causes of film loss, which are often difficult to define. The main reasons are:

1. Production: due to the Beam Splitter Coating process, there may be some acicular film dropping, also known as needle eye, in the production, which is unavoidable in the sputtering coating process itself. In addition, due to the coating of the original piece itself or equipment cleaning reasons, may also cause film.

Optical Coating Supplier

Optical Coating Supplier

2. Transport film dropping: after the glass is unpacked and transported or cut, there is no cushion or uneven pad between the glass sheets as required, which leads to direct contact between the glass sheets. In the process of handling or transportation, the direct relative friction between the glass and the glass film surface results in Aluminum Mirror with Al coating film dropping. This kind of film falls normally is dot form or group form drop film, can use the hand or examine a device to feel or check to rub mark.

3. Corrosive film loss: because the glass film surface in cutting stacking, construction use or cleaning, because of cross construction or use of incorrect methods, make the glass film surface contact with acid, alkali or oxidizing substances, cause the glass film surface is polluted and corroded and film loss. In general, traces of corrosive substances can be found on the film surface or at the site.


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