A glass flask obtained of pickled food was developed as bulb with intern vacuum to tests of encapsulation method for electroluminescent devices. At the lid of glass flask were adapted: two (02) metallic valves to vacuum or insert inert gas, one (01) pressure gauge (with high or low pressures) and one (01) printed circuit board with copper stripes for electrical connections, all these components were sealed with epoxy. In the first investigation was carried out intern vacuum at 76 cm.Hg observing the possible variation of intern pressure by elapsed time (for seven days). In the second investigation were used four (04) incandescent lamps (of 12 V and 10 W) without outer bulb to obtain the tungsten filaments that were polarized under vacuum atmosphere at different situations. After seven (07) days, only an insignificant increase of intern pressure was observed. The bulb with intern pressure at 76 cm.Hg promoted to the tungsten filament at least forty (40) polarizations, while outside the bulb (at room pressure) were obtained only two (02) polarizations with significant degradation. A layer of WO2 (tungsten oxide) with greenish yellow color formed on the surface of tungsten filament and it was obtained by microscopies and confirmed by EDXS measurement.
Biografia do Autor
Emerson Roberto Santos, Escola Politécnica da USP
Doutor em Engenharia Elétrica e pesquisador na área de materiais orgânicos para eletrônica, como exemplo OLEDs e OPVs.
