Fundamental study on the position detection signal analysis for the fibre optical trapping probe

In this study, a novel touch probe for measuring three-dimensional (3D) microcomponents with a high aspect ratio is proposed. By this technique, a dielectric microsphere is optically trapped using an optical fibre and used as a touch probe. To use the trapped microsphere as the touch probe sphere, the intensity of reentering light that is reflected from the surface of a microsphere is sensed as a position detection signal. When the probe is in contact with the surface of an object, the intensity of the reentered light changes and this change is used as the position detection signal. A method for detecting the touch of the probe sphere by using the sensed signal is also analysed in this study.