Antonelli, Terry, Stout & Kraus
Magnetic disc apparatus with thin film head suitable for high-density recording
 A magnetic disc apparatus includes a magnetic disc for recording information; a thin film magnetic head including a magnetic pole structure having an upper magnetic pole tip and a lower magnetic pole tip arranged to provide a magnetic gap at respective end portions thereof for writing and reading information in and from the magnetic disc; a device for rotating the magnetic disc; and a device for positioning the thin film magnetic head; the upper and lower magnetic pole tips having different contours at the respective end portions as viewed from a side confronting the magnetic disc wherein the difference (.DELTA.CW in .mu.m) in the width, along the magnetic gap, of the upper magnetic pole tip and the width, along the magnetic gap, of the lower magnetic pole tip satisfies the relation EQU 0<.DELTA.CW.ltoreq.5000/Tr for the magnetic disc having a track density Tr of 1800 or more tracks per inch. 
Hitachi, Ltd.
G G
G11B G11B
inventional inventional
Yutaka Moriaki Hiroshi Masatoshi Eiji Takashi Hiroshi Makoto Makoto Makoto Tadayuki Hideki Shunichiro Yokuo Shinji
Sugita Fuyama Fukui Tsuchiya Ashida Kawabe Ikeda Saito Morijiri Aihara Iwakura Yamazaki Kuwatsuka Saitoh Narishige