Coating Onto a Prewet Substrate With Low Weber Number Liquid Curtain

In recent years, miniaturization and high precision of the LCD screen used for small display has been developed fast. The thin and high-precision film covering the LCD screen is manufactured by slide coating. In slide coating, however, the distance between the slot and the substrate is too small. On the other hand, curtain coating can avoid the influence of the mechanical disturbance and is also a good method for coating on rugged substrate. Nevertheless, curtain coating has not been applied to the LCD screen because the liquid curtain with small discharge, i.e. small Weber number, causes instabilities of the flow and the free surfaces. In the present study, we performed the experiment of the liquid curtain bridged between the exit of slot die and moving roller under very small Weber number (We ∼0.1). It is found that the surface waves are reduced by using a roller pre-wetted by mists and by changing the viscosity of the liquid. Also, the coating window can be drawn in a plane of surface tension and viscosity. Finally, we tried to explain these phenomena by analyzing the equations of liquid curtain.

A New Method and Characterization for Pollution Preventing of Camera Window

This research is focused on the development of protecting system for window. In detail, we tried to develop pollution preventing system of a glass, mirror, or camera lens. For this, the new method for efficient pollution prevention was designed and the characteristic evaluation for developing the system is partly performed. Formerly, the method using air purge is generally used for preventing the pollution of camera window. However, the conventional method often induces contaminations due to back flow of air purging. These pollutants can be crucial damage to the camera window and peripheral materials especially in clean room condition. And the conventional method always requires air supply, therefore it is difficult to apply the method where air source can not be supplied such as traveling crane located at mountain altitudes. To solve above mentioned the problem, the efficient concept for preventing pollution of camera window is proposed in this research. Without air purging, we proposed the new method using repulsion induced by electrifying dirty or moisture to positive magnetic force with high-voltage charge and then injecting gas to the ITO(Indium Tin Oxide) coating window for generating positive ion. To sum up, in this research, we aim to develop an efficient pollution preventing system for camera window based on the new method through characteristic evaluation and stabilization of the designed system.