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32.2: Multifunctional electrohydrodynamic printing and its industrial applications in flat panel display manufacturing
Author(s) -
Li Huayang,
Duan Yongqing,
Jin Jiangjiang,
Huang Jing,
Zhang Wenzhi,
Guo Tianfu,
Hsu Hsiang Lun,
Huang YongAn
Publication year - 2018
Publication title -
sid symposium digest of technical papers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.351
H-Index - 44
eISSN - 2168-0159
pISSN - 0097-966X
DOI - 10.1002/sdtp.12724
Subject(s) - electrohydrodynamics , materials science , photolithography , lithography , nanotechnology , inkwell , compatibility (geochemistry) , nozzle , nanoscopic scale , 3d printing , encapsulation (networking) , optoelectronics , large format , mechanical engineering , composite material , computer science , optics , electric field , engineering , computer network , physics , quantum mechanics
Inkjet printing has become a robust, effective and powerful technique for display manufacturing due to its compatibility with large‐area substrates, and cost effectiveness. However, conventional inkjet printing that relies on thermal or piezoelectric actuation falls short to fabricate the high‐resolution components, and is inapplicable to highly viscous materials. Electrohydrodynamic (EHD) printing, which adopts electrical field force to pull the fluid flow from the Taylor cone at the nozzle, exhibits the ultra‐high resolution (even to the nanoscale) and excellent compatibility with highly viscous inks. This paper has presented the promising applications of EHD printing in display manufacturing, e.g. micro dams for boundary definition, organic thin films for encapsulation, and micro lens array for light extraction. Dams with width/thickness of 1∼20 μm/0.5∼3 μm have been directly written on test element group border in a cost‐effective and high‐efficient manner, to replace traditional lithography and etching process in boundary definition. By adopting EHD printing to eject smaller droplets, the thickness of the organic layer in thin film encapsulation has been decreased to less than 6 pm, which is far beyond the current industrial level (8∼12 μm), and making the device to be more flexible. Further, micro lens array with diameters ranging from 3 μm to 20 μm have been directly fabricated on the encapsulation layer of OLED, which make light outcoupling more effective.