Life cycle assessment study of a field emission display television device

摘要

Purpose An life cycle assessment (LCA) study of a field emission display (FED) television device was established. The first objective of this study was to get an up-to-date and comprehensive picture by applying the latest developments in the area of LCA, especially concerning the use of nanoparti-cles. In its second part, the study shows a comparison with today's display technologies (i.e. CRT, LCD, plasma) and the timely development of the assessment of a FED television device.Methods This LCA study covers the complete life cycle of a FED television device in accordance with the ISO 14040 standard, from the extraction of raw materials until the final end-of-life treatment in a European WEEE recycling system. Two different functional units were applied in this study: For the in-depth analysis of the FED television device, an entire device along its complete life cycle was considered as functional unit-for the subsequent comparison with today's display technologies, "one square-inch of display during 1 h of active use" was used as an appropriate functional unit. Main data source for the FED device was patent information; ecoinvent was used as default background database. Results and discussion The in-depth analysis of this FED television device shows a clear dominance of the production phase (independently of the impact category). Within the production of such a device, the electronics part (i.e. the printed wiring boards) shows the highest contribution-while, even when focussing on the glass and its various coating layers only, the carbon nanotubes (CNTs) production has a very minor influence. The releases of CNTs during the End-of-Life treatment do not contribute in a relevant manner to the overall impact neither-even when focussing on the "ecotoxicity potential" by using conservative CFs reported for this type of releases. Last but not least, the comparison with the existing television display technologies shows that an FED device has an environmental advantage over all three other technologies using the above stated functional unit of "one square-inch of display during 1 h of active use". Conclusions Traditional impact categories as well as the ecotoxicity factor results in clear environmental advantages for an FED television device when comparing it to the three display technologies used today. Concerning the general issue of evaluating applications of manufactured nanomaterials in LCA studies, this case study shows the high relevance of an adequate integration of nanoparticle releases into LCA studies in order to achieve an actually comprehensive evaluation.