Iwao Yagi

A flexible full‐color AMOLED display driven by OTFTs

Abstract— Organic thin-film-transistor (OTFT) technologies have been developed to achieve a flexible backplane for driving full-color organic light-emitting diodes (OLEDs) with a resolution of 80 ppi. The full-color pixel structure can be attained by using a combination of top-emission OLEDs and fine-patterned OTFTs. The fine-patterned OTFTs are integrated by utilizing an organic semiconductor (OSC) separator, which is an insulating wall structure made of an organic insulator. Organic insulators are actively used for the OTFT integration, as well as for the separator, in order to enhance the mechanical flexibility of the OTFT backplane. By using these technologies, active-matrix OLED (AMOLED) displays can be driven by the developed OTFT backplane even when they are mechanically flexed.

An OTFT-driven rollable OLED display

Abstract— An 80-μm-thick rollable AMOLED display driven by an OTFT is reported. The display was developed so as to be rollable in one direction with an integrated OTFT gate driver circuit. It was successfully operated by an originally developed organic semiconductor, a peri-xanthenoxanthene derivative. The display retained its initial electrical properties and picture quality even after being subjected to 1000 cycles of a roll-up-and-release test with a radius of 4 mm.

47.3: A Rollable AM-OLED Display Driven by OTFTs

We have developed an 80-μm-thick rollable AM-OLED display. The display is driven by an organic TFT backplane for which we have used originally developed semiconductor, a perixanthenoxanthene derivative. The display shows no degradation in a 4 mm-radius roll-up-and-release cycle of 1000 times.

63.2: Distinguished Paper: A Full-Color, Top-Emission AM-OLED Display Driven by OTFTs

We have developed an integration architecture for high-resolution organic-TFT (OTFT) arrays with top pixel electrodes on a plastic film. In this architecture, no damage isolation method of organic semiconductor (OSC) in a photolithographically defined resolution is employed. All the insulators in the backplane consist of organic polymers, enhancing both the mechanical flexibility of the backplane and the manufacturing throughput. These technologies have been successfully applied to produce a flexible, full-color and top-emission active-matrix organic light-emitting diode (AM-OLED) display on a plastic substrate with a resolution of 80 ppi.

A flexible OLED display with an OTFT backplane made by scalable manufacturing process

— A full-color top-emission AMOLED display driven by an organic TFT backplane manufactured using a scalable, lift-off-free, and shadow-mask-free process has been developed. It was shown that cost-efficient copper can be used for S/D electrodes. The display has shown no significant degradation over a storage life of more than 10 months and operation over 25 hours during which the display is bent over 10,000 times.

36.1: Invited Paper: Rollable OLED Display Driven by Organic TFTs

We have developed a 4.1-in FWQVGA rollable AM-OLED display driven by organic TFTs. For an organic semiconductor, a peri-Xanthenoxanthene derivative has been developed. We have also developed an integrated gate-driver circuit. This enables to eliminate rigid gate-driver ICs and roll up the OLED display with bending radius of 4 mm.

10.5L: Late-News Paper: All-Organic TFT-Driven QQVGA Active-Matrix Polymer-Dispersed LCD with Solution-Processed Insulator, Electrodes, and Wires

A high-performance pentacene organic-TFT backplane with a solution-processed novel poly(4-vinylphenol)-based dielectric and a solution-processed organo-silver electrode/wire has been developed below 150°C. The all-organic-TFT backplane has been successfully applied to drive a QQVGA active-matrix (AM) polymer-dispersed (PD) LCD with a resolution of 79 dpi and a display size of 2.5 inches.

44.2: Distinguished Paper: A Reliable Flexible OLED Display with an OTFT Backplane Manufactured Using a Scalable Process

We have developed a full-color, top-emission, AM-OLED display driven by organic TFT backplane manufactured using a scalable, lift-off free and shadow mask free, process. Low-cost copper electrode is used for S/D electrodes. The display shows no significant degradation for the storage life > 2 month and operation period > 25 hours with 10000 times bending.

Solution-processed organic TFT array for active-matrix LCDs on a plastic substrate

— Organic TFTs (OTFTs) have been developed with a novel solution-processed gate insulator of poly(4-vinylphenol) (PVP) with the addition of octadecyltrichloro-silane (OTS) and a solution-processed organo-silver electrode/wire to improve the performance of an OTFT and to maked high-throughput-manufacturing process possible. Solution-processed PVP has also employed for a buffer layer on a plastic substrate. The OTFT backplane with these solution-based organic-material technologies has been successfully applied to drive a 2.5-in. QQVGA (160 × 120 pixels) AMLCD with a resolution of 79 dpi.

An flexible OLED driven by OTFT backplane manufactured using a scalable process

A full-color, top-emission active-matrix organic light-emitting diode display build on a flexible substrate (flexible OLED) has been successfully driven by organic-TFTs made by a scalable manufacturing process (lift-off and shadow mask free process). The OTFTs were fabricated with low cost metal (copper and aluminum) electrodes. The backplane architecture was developed at low temperatures (<150°C) with solution-processed organic dielectrics. The fabricated TFTs are reliable against bending stress with 2-mm radius. With this ultra high flexibility of the OTFT, the display shows no significant degradation for an operating period >25 hours with more than 10,000 times bending.