Ryuzo Fukao

Improvement of luminous efficiency in ZnS:Tb, F thin-film electroluminescent devices using ferroelectric PbTiO3 and silicon nitride as carrier accelerating buffer layers

Thermal carrier accelerating action and its effect on electroluminescence performance by insertion of a buffer layer have been systematically studied in ZnS:Tb, F thin-film electroluminescent (EL) devices. The EL devices studied have a structure of ITO/PbTiO3/ZnS:Tb, F/SiNx/Al. The result shows that the brightness obtained is rather low, but luminous efficiency is high compared to that of EL devices without an SiNx buffer layer. A mechanism for the improvement of luminous efficiency is postulated, and the role of the buffer layer is also discussed.

A dual color basis tunable color EL device employing ZnS:Tb, F/ZnS:Mn stacked phosphor layers with color filters

A tunable color thin-film electroluminescent (EL) device having a stacked structure of ZnS:Tb, F/ZnS:Mn with red and green colored filters was developed. The obtained red and green emissions have high enough luminance to be considered as a practical tunable color display panel, though the color tone of the green emission approaches yellow-green. It was confirmed that varying the color between red and green can be easily done by changing the filters and applied voltage. This device should be useful for a wide variety of applications in such fields as active information display systems. >

High-brightness low-driving-voltage green color thin-film electroluminescent devices

Abstract High-performance green-color emitting ZnS:Tb,F thin-film electroluminescent (EL) devices are developed. These EL devices are constructed with a first insulating layer of ferroelectric PbTiO3 film, next a phosphor layer and then a second insulating layer of silicon nitride film prepared by plasma CVD. Green color emission of 5300 cd/m2 is obtained at a driving voltage of 180 V in the EL device using a PbTiO3 film deposited at 650°C.