3.4-Inch Quarter High Definition Flexible Active Matrix Organic Light Emitting Display with Oxide Thin Film Transistor

Abstract

In this paper, we report a 3.4-in. flexible active matrix organic light emitting display (AMOLED) display with remarkably high definition (quarter high definition: QHD) in which oxide thin film transistors (TFTs) are used. We have developed a transfer technology in which a TFT array formed on a glass substrate is separated from the substrate by physical force and then attached to a flexible plastic substrate. Unlike a normal process in which a TFT array is directly fabricated on a thin plastic substrate, our transfer technology permits a high integration of high performance TFTs, such as low-temperature polycrystalline silicon TFTs (LTPS TFTs) and oxide TFTs, on a plastic substrate, because a flat, rigid, and thermally-stable glass substrate can be used in the TFT fabrication process in our transfer technology. As a result, this technology realized an oxide TFT array for an AMOLED on a plastic substrate. Furthermore, in order to achieve a high-definition AMOLED, color filters were incorporated in the TFT array and a white organic light-emitting diode (OLED) was combined. One of the features of this device is that the whole body of the device can be bent freely because a source driver and a gate driver can be integrated on the substrate due to the high mobility of an oxide TFT. This feature means “true” flexibility.

Photo-Leakage Current of Thin-Film Transistors with ZnO Channels Formed at Various Oxygen Partial Pressures under Visible Light Irradiation

“…Liquid crystal displays and organic light-emitting diode displays have been demonstrated by using oxide TFT backplanes. [1][2][3] In addition, oxide TFTs have a potential for achieving transparent electronics.…”

An 8-bit Data Driving Scheme Based on Two-Step Digital-to-Analog Conversion for Integrated Data Drivers of Active-Matrix Organic Light-Emitting Diodes

“…Active-matrix organic light-emitting diode (AMOLED) displays have remarkably advanced over the past decade and found major applications in mobile displays. [1][2][3] Unlike thin-film transistor-liquid crystal displays (TFT-LCDs) of which the backplane technology is the amorphous silicon thin-film transistor (a-Si:H TFT), for now, AMOLED displays mostly use the polycrystalline silicon thin-film transistor (poly-Si TFT) because of its current driving capability and stability to bias temperature stress. [4][5][6] The poly-Si TFT backplane is the technology of choice for the above reason, and it is also widely agreed that it possesses a strong potential to integrate circuits including data and scan driver circuits, microprocessors, memories, and power supply circuits on the substrate.…”

Fabrication of Flexible Amorphous Indium-Gallium-Zinc-Oxide Thin-Film Transistors by a Chemical Vapor Deposition-Free Process on Polyethylene Napthalate

“…Flexible active-matrix organic light-emitting diode (AMOLED) displays on plastic substrates have been attracted great attention, because they can be thinner, lighter, bendable and unbreakable as compared to the displays based on traditional glass substrate 1,2 In order to realize flexible AMOLED displays, we need to fully consider two key requirements that satisfied the demand of production and application. The first requirement is to develop TFT technology to obtain a TFT panel with good uniformity and excellent stability.…”