End of life liquid crystal displays recycling: A patent review

A huge quantity of end-of-life liquid crystal displays (LCD) is collected, every year, around the world. Nowadays, this equipment is disassembled, for the removal of hazardous components (e.g. the backlight fluorescent lamps), and the resulting panel is stored. The reason is the significant content of valuable fractions (e.g. glass, metals and liquid crystals) and the lack of a recycling process, sustainable from an economic and an environmental point of view. Considering the relevance of this critical issue, the scientific community focused on the development of different recovery strategies, summarized in several available reviews. Nevertheless, the literature has not yet dealt with the technological innovation aspect. With the aim of filling this gap, the present review presents the international patents about LCD recycling, from 1999 to 2017, using the Espacenet platform, that has access to all the most relevant patent databases worldwide. The inventions include a first waste disassembling, followed by the classification of the target fractions and the recovery of metal (e.g. indium, indium tin oxide) and nonmetal (e.g. glass, polarizing film, liquid crystal) components.