Paper-like electronic displays: Large-area rubber-stamped plastic sheets of electronics and microencapsulated electrophoretic inks

Electronic systems that use rugged lightweight plastics potentially offer a ttractive characteristics (low-cost processing, mechanical flexibility. lar ge area coverage, etc.) that are not easily achieved with established silic on technologies, This paper summarizes work that demonstrates many of these characteristics in a realistic system: organic active matrix backplane cir cuits (256 transistors) for large (approximate to5 x 5-inch) mechanically f lexible sheets of electronic paper, an emerging type of display. The succes s of this effort relies on new or improved processing techniques and materi als for plastic electronics, including methods for (i) rubber stamping (mic rocontact printing) high-resolution (approximate to1 mum) circuits with low levels of defects and good registration over large areas, (ii) achieving l ow leakage with thin dielectrics deposited onto surfaces with relief, (iii) constructing highperformance organic: transistors with bottom contact geom etries, (iv) encapsulating these transistors, (v) depositing, in a repeatab le way, organic semiconductors with uniform electrical characteristics over large areas, and (vi) low-temperature (approximate to 100 degreesC) anneal ing to increase the on/off ratios of the transistors and to improve the uni formity of their characteristics. The sophistication and flexibility of the patterning procedures, high level of integration on plastic substrates. la rge area coverage, and good performance of the transistors are all importan t features of this work. We successfully integrate these circuits with micr oencapsulated electrophoretic "inks" to form sheets of electronic paper.