A DESIGN CONCEPT OF ARRAY HEADS

This paper describes a novel design concept and experimental hardware data of array heads for close-packed track recording, The heads are ba tch fabricated on wafers in a linear fashion. These 60 turn thin-film inductive heads are designed with 6 mu m pitch helical coils and plana r side-by-side P1/G/P2 yokes structure, The linear head array is place d along the upstream-to-downstream direction of the track. By skewing the array slightly off the track direction, each head of the array ali gns to an individual track, In this case, the track pitch is about 5 m u m, which is the yoke height. With this head arrangement, even though a thermal expansion causes the head-to-head distance to increase alon g the upstream-downstream direction, it does not cause a thermal induc ed track misregistration problem, The increased head-to-head distance only affects the timing of signals between tracks, which can be compen sated by the channel electronics, Thus, the thermal induced track misr egistration problem is eliminated using this design, The guard bands b etween tracks are not necessary, and a close-packed track recording is possible. A state of the art head impedance of the 60-turn head is ob tained: 11 Omega. and 0.40 mu H. The gap-to-gap pitch is 100 mu m. The overall head-to-head isolation is greater than 50 dB at 10 MHz. Such a large isolation is realized by suppressing the capacitive coupling b etween lead wires using a ground plane and grounded wall structures, T he tight winding of the helical coils reduces the magnetic coupling be tween the heads.