The cleaning of achromatic doublet lens can be divided into pre-coating and post-coating. Processors should adopt different cleaning methods according to the different pollutants before and after coating, and select special achromatic doublet lens cleaner before coating.
1. Cleaning before coating
The main pollutants for cleaning before coating are core oil (also known as edge polishing oil, also known as core fixing and core taking), which refers to the process selected to obtain the specified radius and core accuracy, fingerprints, dust and so on. Because of the strict requirement for lens cleanliness in coating process, the choice of cleaning agent is very important. Considering the cleaning ability of a detergent, we should also consider its corrosiveness and other aspects. Cleaning before coating is usually done in the same way as cleaning after grinding.
2. Cleaning after coating
Generally, it includes cleaning before painting, cleaning before joining and cleaning before assembly. Among them, cleaning before joining (joining refers to a process in which two lenses are bonded with photosensitive glue to form a prescribed shape to meet the requirement of one-time processing and forming, or to produce a relatively special curvature and transmittance) is the most stringent one. The main pollutants to be cleaned before joining are mixtures of dust and fingerprints, which are not very difficult to clean. However, there are very high requirements for lens surface cleanliness, and the cleaning method is the same as the previous two cleaning processes. Because the coating is vulnerable to strong alkaline damage, the strong alkaline cleaning agent can not be used after coating, and special achromatic doublet lens cleaning agent after coating is needed. The cleaning agent does not damage the film layer, has strong decontamination power and can preserve the film layer intact.
Therefore, after coating achromatic doublet lens,
it is generally recommended to use professional cleaning agent for achromatic doublet lens after coating.