Removal of thin hard coating on glass substrate by collision of nanometer‐sized particles accelerated in high‐intensity ultrasonic field

Abstract

The aim of this study is to establish a fundamental recycling technology for optical lenses. In industry, a common conventional technique for cleaning the surface of a small object such as an optical lens is through the use of ultrasonic cavitation. However, the intensity of shock waves caused by the cavitation is difficult to control. The authors have considered that the substances that adhere to lens surfaces, such as hard optical coatings and stains, are removable using collisions, against the lens surface, of many tiny particles that are accelerated by a high‐intensity ultrasonic field. Some physical parameters that dominate the removal effect have been changed systematically to illustrate the surface‐refreshing process for lenses in the experiments. The authors worked to experimentally clarify the particle collision effect on the removal. In addition, the acoustic field was analyzed using finite‐element method. The authors have also attempted to elucidate the principle of the removal technique throug...