公开(公告)号：JP2000132804A

公开(公告)日：2000-05-12

申请号：JP27595299

申请日：1999-09-29

Applicant: IBM

Inventor： SALO MICHAEL P ,  WALLASH ALBERT JOHN

IPC: G11B5/39 ,  G11B5/00 ,  G11B5/02 ,  G11B5/09 ,  G11B5/40 ,  G11B5/455

Abstract: PROBLEM TO BE SOLVED: To improve the magnetic stability of an MR head by writing the additional writing pulse having the specified polarity in the case the last writing pulse does not have the specified polarity after a group of writing pulses is written in. SOLUTION: A writing head polarity controller responds to a polarity signal, and the writing head is energized by one or plural additional pulses having the specified polarity when the polarity signal shows that the last writing pulse among a group of pulses does not have the specified polarity. The writing head is preferably energized by only one additional pulse. When the last writing pulse does not have the specified polarity, a pulse activating signal is outputted, and by this pulse activating signal, a writing driver is operated so that the writing head is energized by one or plural additional pulses having the specified polarity. Or, the writing head is energized by one or plural additional pulses having the specified polarity without considering the polarity of the last writing pulse.

公开(公告)号：DE69615456T2

公开(公告)日：2002-05-02

申请号：DE69615456

申请日：1996-05-24

Applicant: IBM

Inventor： HUGHBANKS TIMOTHY SCOTT ,  ROBERTSON NEIL LESLIE ,  VOLDMAN STEVEN HOWARD ,  WALLASH ALBERT JOHN

IPC: G11B5/10 ,  G11B5/11 ,  G11B5/31 ,  G11B5/39 ,  G11B5/40 ,  G11B5/596 ,  G11B5/00 ,  G11B19/04

Abstract: A magneto-resistive read head (107) having a "parasitic shield" (124) provides an alternative path for currents associated with sparkovers, thus preventing such currents from damaging the read head (107). The parasitic shield (124) is provided in close proximity to a conventional magnetic shield (113, 115). The electrical potential of parasitic shield (124) is held essentially equal to the electrical potential of the sensor element (111). If charges accumulate on the conventional shield (113, 115), current will flow to the parasitic shield (124) at a lower potential than would be required for current to flow between the conventional shield (113, 115) and the sensor element (111). Alternatively, conductive spark gap devices (203, 206) are electrically coupled to sensor element leads and to each magnetic shield (201, 202). Each spark gap (203, 206) device is brought within very close proximity of the substrate (207) to provide an alternative path for charge that builds up between the sensor element (213) and the substrate (207) to be discharged. The ends of the spark gaps (203, 206) that are brought into close proximity of the substrate are preferably configured with high electric field density inducing structures which reduce the voltage required to cause a sparkover between the spark gap device (203, 206) and the substrate (207).

公开(公告)号：SG47371A1

公开(公告)日：1998-04-17

申请号：SG1995002268

申请日：1994-10-25

Applicant: IBM

Inventor： BARLOW IRMELA CHRISTIANE ,  GARFUNKEL GLEN ADAM ,  HOYT ROGER F ,  MARELLO VINCENT ,  MCWILLIAMS CHRISTIAN JR ,  WALLASH ALBERT JOHN

IPC: G11B5/02 ,  G11B5/31 ,  G11B5/39 ,  G11B5/40

Abstract: Electrically conductive protective devices provide a current path shunting the magnetoresistive (MR) sensor element (35) in a magnetic head assembly (21) to discharge static electrical charges without damage to the MR sensor element. A variable conductance device (80) having a nonlinear current-voltage characteristic, such as a pair of Schottky diodes, for example, is connected between the MR sensor element leads in parallel with the MR sensor element or between each MR sensor element lead and a ground reference, the MR sensor element magnetic shields, for example, to provide a discharge current bypass path. Alternatively, one or more bleed resistors (133) are connected between the MR sensor element leads and a ground reference to provide the current bypass path thus allowing any static charge to bleed off.

公开(公告)号：DE69615456D1

公开(公告)日：2001-10-31

申请号：DE69615456

申请日：1996-05-24

Applicant: IBM

Inventor： HUGHBANKS TIMOTHY SCOTT ,  ROBERTSON NEIL LESLIE ,  VOLDMAN STEVEN HOWARD ,  WALLASH ALBERT JOHN

IPC: G11B5/10 ,  G11B5/11 ,  G11B5/31 ,  G11B5/39 ,  G11B5/40 ,  G11B5/596 ,  G11B5/00 ,  G11B19/04

Abstract: A magneto-resistive read head (107) having a "parasitic shield" (124) provides an alternative path for currents associated with sparkovers, thus preventing such currents from damaging the read head (107). The parasitic shield (124) is provided in close proximity to a conventional magnetic shield (113, 115). The electrical potential of parasitic shield (124) is held essentially equal to the electrical potential of the sensor element (111). If charges accumulate on the conventional shield (113, 115), current will flow to the parasitic shield (124) at a lower potential than would be required for current to flow between the conventional shield (113, 115) and the sensor element (111). Alternatively, conductive spark gap devices (203, 206) are electrically coupled to sensor element leads and to each magnetic shield (201, 202). Each spark gap (203, 206) device is brought within very close proximity of the substrate (207) to provide an alternative path for charge that builds up between the sensor element (213) and the substrate (207) to be discharged. The ends of the spark gaps (203, 206) that are brought into close proximity of the substrate are preferably configured with high electric field density inducing structures which reduce the voltage required to cause a sparkover between the spark gap device (203, 206) and the substrate (207).

公开(公告)号：SG51705A1

公开(公告)日：1998-09-28

申请号：SG1996007295

申请日：1996-04-04

Applicant: IBM

Inventor： HUGHBANKS TIMOTHY SCOTT ,  ROBERTSON NEIL LESLIE ,  VOLDMAN STEVEN HOWARD ,  WALLASH ALBERT JOHN

IPC: G11B5/10 ,  G11B5/11 ,  G11B5/31 ,  G11B5/39 ,  G11B5/40 ,  G11B5/596 ,  G11B5/00 ,  G11B21/00

Abstract: A magneto-resistive read head (107) having a "parasitic shield" (124) provides an alternative path for currents associated with sparkovers, thus preventing such currents from damaging the read head (107). The parasitic shield (124) is provided in close proximity to a conventional magnetic shield (113, 115). The electrical potential of parasitic shield (124) is held essentially equal to the electrical potential of the sensor element (111). If charges accumulate on the conventional shield (113, 115), current will flow to the parasitic shield (124) at a lower potential than would be required for current to flow between the conventional shield (113, 115) and the sensor element (111). Alternatively, conductive spark gap devices (203, 206) are electrically coupled to sensor element leads and to each magnetic shield (201, 202). Each spark gap (203, 206) device is brought within very close proximity of the substrate (207) to provide an alternative path for charge that builds up between the sensor element (213) and the substrate (207) to be discharged. The ends of the spark gaps (203, 206) that are brought into close proximity of the substrate are preferably configured with high electric field density inducing structures which reduce the voltage required to cause a sparkover between the spark gap device (203, 206) and the substrate (207).