Organic multi-color electroluminescence display with fine pixels

We present an RGB multi-color electroluminescence (EL) display, in which a blue organic EL display was combined with color changing media (CCM). The CCM were basically made up of organic fluorescent media which changed the emission color from blue to green or red. For the blue organic device, we improved a multi-layer structure in which a distyrylarylene (DSA) emitting layer included a slight amount of an amino-substituted DSA dopant. We achieved a high efficiency of 6 lm/W and a half life time of 20000 h at an initial luminance of 100 cd/m(2). Furthermore, the device showed a very fast response time of less than 600 ns. It is possible to operate a simple-matrix panel with 500 lines under a video-rate driving. In order to realize the simple-matrix panel with a large number of micro-pixels, we found new fabrication methods for micro-patterning of the CCM and a cathode. We succeeded in patterning the CCM by a photolithographic method. In addition, the cathode patterning method was developed, by which the cathode was found to be automatically separated to form the pixels by the use of inter-insulator ribs formed on anodes. By using the latter method for the fabrication of a blue mono-color display, we realized a 5 inch QVGA (quarter VGA) display, which imaged video-rate pictures with 256 gray scale. To our knowledge, this is the first report of an organic EL display with high resolution, video-rate pictures (60 frames/s), a large number of pixels (240 x 960) and full gray scale (256). (C) 1997 Elsevier Science S.A.