An inkjet printed stripe-type color filter of liquid crystal display

Abstract

In this paper, we propose a comprehensive concept and new design of a drop-on-demand (DOD) inkjet printing process for fabricating color filter (CF) layers of liquid crystal displays (LCDs) onto the structured surfaces of flat substrates, composed of 'physical sidewalls' for aligning and controlling the liquid morphology. Several fundamental guidelines of the design have been addressed in current inkjet-printing techniques. Using a droplet generator (printhead) of the deposition system, the color-ink drops can be jetted and placed over the specific domains, where the sidewalls align the flow merged from a stream of droplets and fulfill the coverage of the defined areas, in which the geometrical relations correlating the droplets and sidewalls are explicitly expressed in the study. According to the results of the simulation and analysis, the proposed sidewalls, acting as the physical barriers, can control the liquid morphology through the simple geometric factors such as sidewall widths, heights and contact angles. The experimental results showed that the solid RGB color layers were self-assembled from the liquid droplets and formed with the uniform thickness, except for the neighborhood of the sidewalls. It indicated that the sidewalls serving as 'physical barriers' had a remarkable effect in confining and self-aligning the droplet flow within the desirable regions. This inkjet-printing method would alternatively offer one cost-effective and high-flexibility method for the production of the versatile LCD CF, thus being particularly beneficial for large-area printing and flexible substrates.

Inkjet Printing of Microcomponents: Theory, Design, Characteristics and Applications

“…Positioning accuracy together with morphological formation of droplet deposition that will be discussed in next Section 3 can be significantly influenced by the deviation from the targeted values. And this technical difficulty, in some situations permitted (Chen et al, 2010), may be compensated in terms of tuning substrate properties and printing algorithms as follows. Typical jetting process of a micro droplet generated through a tiny nozzle, from initial to necking stages; (Bottom) dynamic evolution of droplet formation in tens of microseconds.…”

“…As can seen in Figure 4, an inkjet printing platform prototype, laboratory-designed and developed for inkjet printing of color filters (Chen et al, 2010) by Industrial Technology Research Institute (www.itri.org.tw) in Taiwan, illustrates a common configuration primarily comprising the printhead cartridge, substrate carrier, movable stage and rotator, CCD camera and microscopy, base and gantry frame. With the printhead cartridge fixed on the gantry frame, this platform can perform DOD inkjet printing algorithm by moving the motored stage to deliver the substrate in x-y coordinates so that the imaging pattern is online input and completed through a friendly user interface (PC-based LabView).…”

“…Nevertheless, in the recent years, much attention of studies in academics and industries as well is paid to the uses of various materials in the inkjet printing processes, including nanoparticle metals (Szczech et al, 2002;Kang et al, 2010), bio-chemicals (Busato et al, 2007;Fuchs et al, 2011), colloidal polymers (MacFarlane et al, 1994;Biehl et al, 1998;Jeon et al, 2005;Chen et al, 2008), coloring and light emitting materials (Bale et al, 2006;Chen et al, 2010;Chang et al, 2011), transistors and semiconductors (Sirringhaus, et al, 2000;Han et al, 2009;Hinemawari et al, 2011), and so forth. Compared to conventional two deposition techniques, i.e.…”

“…Primary three colors of red (R), green (G), and blue (B) can be firmly formed on the receptor layer of a substrate through a series of RGB coloring, ink fixing, and curing of receptor layer, where the substrate requires film coating for absorbing the color inks prior to inkjet printing. Based on the this kind of application, more persisting efforts were made within recent years about the improvement of ink formulas (Kim et al, 2009;Chang et al, 2011), surface treatments and characteristics (Koo et al, 2005;Chen et al, 2010), and large-area and active lighting (Bale et al, 2006). In a similar development way, more extensive studies for inkjet printing applications were also directed to other fields including biochips (Xu et al, 2005;Gutmann et al, 2005), optical microlenses (Nallani et al, 2006;Chen et al, 2009), microelectromechanical systems (Fuller et al, 2002;Cho et al, 2006;Alfeeli et al, 2008), and electronic components (Lee et al, 2005;Scandurra et al, 2010;Perelaer et al, 2010).…”

Directional wetting on patterned surfaces

“…Most recently, the possibilities of printing were even extended to three-dimensional objects. The application areas for inkjet technology include displays [6,87], the chemical industry [88,89], electronic components [90][91][92][93], and a large emerging field comprises the life sciences [94,95]. For all these applications a high speed and a high printing quality are required.…”