Print mask design for inkjet functional printing.

摘要

For the past several decades inkjet technology has been shown to be a useful tool for fabricating anything from three dimensional objects to electrical devices and biological sensors. From a manufacturing perspective, it is important to functionalize a substrate with material in as timely a manner as possible while maintaining optimal functionality and satisfying hardware limitations. Of particular interest in previous work has been the effect of drop coalescence on print quality. Random variations in drop volume and drop placement make coalescence a stochastic process. Therefore, this study investigates the occurrence of coalescence between adjacently printed drops, considering drop impact, spreading, evaporation, and variation in drop volume and drop placement, especially for a high vapor pressure ink and an ink-substrate system with small contact angle hysteresis. This work also examines how coalescence affects the uniformity of printed pairs of drops and printed lines as well as the functional performance of printed lines. The results indicate that film uniformity and optimal functional performance can be achieved by minimizing ink migration. The results further show that using probability of coalescence as a cost function in order to minimize ink migration is a viable strategy.;Since the introduction of multiple nozzle print-heads, print mask design has become a means of controlling the firing sequence of nozzles in a print-head. Given a printing system, this study provides a detailed introduction to define essential items involved in print mask design, such as print mode, print mask, nozzle mapping, and deposition time. This work also develops a modification of the direct binary search (DBS) algorithm incorporating the probability of coalescence developed herein as an error measure to be minimized in order to design print masks for optimal performance. Applying this design to an in-house inkjet functionalization system with Pd hexadecanethiolate onto Si and SiO2 substrates demonstrates the utility of this proposed design to optimize image quality and device functionality.