EL characteristics of a TFEL/TFT stacked structure display device driven by a HV-Si·TFT circuit

TFEL/TFT stacked structure display devices were fabricated onto a quartz substrate. By using a HV-TFT circuit as the basis of a TFEL/TFT device, an EL device on the TFT circuit can be switched at a sufficiently low signal line voltage of V_s=2-3 V. The maximum brightness of the TFEL/TFT device is 230 cd/m² and the ON/OFF brightness ratio is more than 90 between Vs=0 and Vs=4 V at a V_app frequency of 5 kHz and a voltage of 50. Evaluation of the dynamic behavior of TFT circuits using multichannel HV-Si·TFT´s showed that the rise time of the fundamental TFT circuit at the EL driving point of the circuit was about 20 μs and that the hold time of the circuit was about 70 mS. The rise time and the fall time of the luminescence were each about 20 μs. The memory characteristics of the TFEL/TFT device showed that the hold time of the luminescence was about 40 mS. These dynamic characteristics of the TFEL/TFT stacked structure device satisfy the conditions required for a flat panel display