Displacement Measurement for High Speed Tribological Measurement Using Oscillating Optical Fiber Probe

Abstract

Lubrication of the head disk interface (HDI) of a hard disk drive is achieved by coating a magnetic disk with a liquid lubricant film of monolayer thickness. It is important to clarify the tribological properties of the lubricant film for optimal lubrication of the HDI. In our previous study, we developed a highly sensitive method to measure shear force, which we called the "fiber wobbling method (FWM)." This method enables us to measure the viscoelastic properties of molecularly thin lubricant films. However, the shearing speeds were less than a few hundred µm/s, which is much slower than expected for the HDI. In this study, we developed a novel technique to measure displacement with a wide measuring range and high sensitivity, which will be essential for high speed tribological measurement using FWM.