Retardation of the onset time for signal dropout arising from wear debris using diamond-like carbon overcoats on the VCR head

Abstract

An investigation was conducted to examine the effects of diamond-like carbon (DLC) overcoats on the wear durability of the VCR head and the signal dropout caused by wear debris while the VCR is in operation. Approximately 40-nm-thick DLC films were deposited directly on the Mn-Zn ferrite head pole by an electron cyclotron resonance (ECR) system using CH/sub 4/ source gas. The deposition temperature was maintained at below 100/spl deg/C to prevent deterioration of the epoxy resin attached to the head. From the experiment we were able to discover that DLC films accumulated successively from the bottom of the grooves on the head surface smoothing out the surface. In general, DLC heads outperformed the bare heads. The head life is increased significantly by the wear durability of DLC films and the continuous supply of lubricating DLC films. We were also able to discover that leftover DLC films along the head edge provide continuous lubricity on the rubbing head surface during use. Furthermore, most of the wear debris was more readily expelled from the DLC head surface than from the bare head. Therefore, the onset time of the signal dropouts was found to be delayed six times in DLC heads in the still frame mode.