The etching in ITO conductive glass in PT touch screen industry is far from the acid etching in FPC, and the etched metal is also different. The former needs to etch indium tin oxide, while the latter needs to etch copper. The composition of the etching solution used is very different. The mixture of nitric acid and hydrochloric acid is generally used in the front (it is also reported that laser etching is used instead of chemical method), and ferric chloride or sodium chlorate is used in the back (a few manufacturers use copper chloride).