Exposure device
The exposure device is a tool normally used for photo engraving in gravure , screen printing , offset printing and electronic circuit board manufacturing.
Photocomposition
From around the 1950s, photo typesetting gained in importance, with the writing being on a photo template, a disc or a strip with a negative type (see Intertype photo setter , monophoto ). The characters were individually aligned in the exposure device and exposed on photo paper or film . In the commercial sector also came during this period Diatype -Fotosatzgerät on the market.
Phototypesetting developed technically, but reached the limits of mechanical feasibility. From the mid-1980s onwards, it faced strong competition from digital typesetting (see: Typesetting calculator , desktop publishing ), which ousted it in the 1990s.
PCB manufacturing
In printed circuit board production, the conductor tracks are usually produced photolithographically by applying a thin layer of light-sensitive photoresist to the surface of the plate, which is still completely metallized. After the photoresist has been exposed through a mask with the desired circuit board layout, depending on the photoresist used, either the exposed or the unexposed portions of the lacquer are soluble in a suitable developer solution and are removed. If the printed circuit board treated in this way is placed in a suitable etching solution (e.g. iron (III) chloride or sodium persulfate dissolved in water or with hydrochloric acid + hydrogen peroxide ), only the exposed part of the metallized surface is attacked; the parts covered by the photoresist are retained because the lacquer is resistant to the etching solution.
Individual evidence
- ↑ Forschungszentrum Karlsruhe 1996 Material flows in the production of printed circuit boards Archive link ( Memento of the original from January 15, 2015 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 729 kB) .
