Influences of electron beam irradaiton on misting and related surface condition on sapphire lens

In order to explain the misting-free treatment by sheet electron beam irradiation (SEBI) for sapphire lens setting on endoscope top, influences of SEBI on surface energy are investigated. The SEBI increases surface energy, resulting in force-distance curve sed for atomic force microscope. Based on the results of X-ray photoelectron spectroscopy, the SEBI enhances the bonding rates of -C-O- and -C-O-O- and decreases -C-C- bonding rate. On the other hand, influences of SEBI on surface water wettability are investigated. The SEBI enhances the wettability of the sapphire surface for water, n-hexadecan, and 1-bromonaphthalene. Since the adhesion molecular change coincides with the surface energy change, the dipole of adhesion molecular is the dominant factor to control the surface energy. In order to explain to the dipole factor change, the electron charge is measured, too. From the results, the surface energy change can be explained by the adhesion molecular change and electron charging.