Fabrication of OLED display by an ultrashort laser: selective patterning of thin metal electrode

Abstract

Organic light emitting diode (OLED) is now in practical use and also a subject of active research and development. In industrial production of OLED displays, one of the key technologies is patterning of electrodes, especially a metal cathode, which is usually made on a thin layer of organic electro-luminescence (OEL) compounds. Difficulties in machining of the OLED come from the fact that the OLED has multi-layered structures consisted from very thin layers of different materials, one of which is a highly heat-and chemical-sensitive organic material. The typical OLED sample has indium tin oxide (ITO) electrode of about 150 nm thick at the bottom. The organic electro-luminescence material of less than 200 nm is deposited on it and the top is aluminum electrode of 100 to 150 nm thickness. We have constructed a fabrication system of the OLED by using an ultrashort fiber laser in the patterning of aluminum electrode and fabricated a display panel successfully. The system has several advantages comparing to other methods currently used. To investigate the process in detail, we have constructed two ultra-fast photography systems, with either subpicoseconds or nanoseconds time resolution, and carried out the time-resolved observation of the process. It is found that the underlying layer affects much to the machinability of the top metal layer. The ITO layer seems to enhance the machining efficiencies of the aluminum electrode: the ablated spot size becomes larger for that on ITO, even though the laser pulse energy is kept constant.

Self-aligned, laser-cut organic electrochemical transistors

“…Complementary inverters tend to be more efficient due to lower power consumption but require the ability to pattern multiple active materials [16]. Laser manufacturing techniques have been used in the fabrication of myriad electronic components [17][18][19]. Some efforts into laser-based patterning of OECTs have been made on flexible substrates but the technique resulted in a heat affected zone due to the decomposition of the PEDOT as it was polymerized onto the substrate before cutting [20].…”

Manufacturing conductive patterns on polymeric substrates: development of a microcontact printing process

“…The integration of high-resolution conductive structures into polymer devices by using a low-cost, rapid, and accurate manufacturing technique is important for the future of the microfluidic [1], photovoltaic [2], flexible printing [1,3,4], optics [2,5], and organic electronics [2][3][4][6][7][8] industries. For example, in the field of microfluidic devices, conductive features can be used to address the needs for electrical pathways, sensing, manipulation of fluids and particles, and local heating, with applications in electromagnetics, biochemistry, and cell biology [1,9,10].…”

Patterning of conducting layers on breathable substrates using laser engraving for gas sensors

“…Developing fast and robust routes to produce patterns of electrically conducting materials on various isolating substrates has been an ongoing area of research for decades and is providing the “baseline” for all produced electrical and electronic circuits. The use of laser equipment to cut and engrave materials is well established and used extensively throughout a wide range of industries . The resolution of the resulting pattern is dependent on the quality of the laser engraver and is adjustable by following the parameters from the calibration.…”