Patents by Inventor Shyam C. Das

Shyam C. Das has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5559654
    Abstract: Process for fabricating a thin film head for high track density recording defines an easy axis parallel to the track in the narrow poletip without a need of a very high magnetic field in the plating cell. Narrow poletips of equal widths of P1 and P2 are obtained. The process includes sheet depositing a magnetic layer, then depositing a sheet of gap material, and then depositing a sheet of another magnetic layer. This operation can be done either by a vacuum technique or by an electroplating process. If it is done by vacuum processing, all the three depositions can be done in one pumpdown. Since the sheet magnetic films are deposited, the demagnetizing field is very small, and a small orienting field is necessary unlike the large field required in the prior art.
    Type: Grant
    Filed: January 23, 1995
    Date of Patent: September 24, 1996
    Inventor: Shyam C. Das
  • Patent number: 5404635
    Abstract: Process for fabricating a thin film head for high track density recording defines an easy axis parallel to the track in the narrow poletip without a need of a very high magnetic field in the plating cell. Narrow poletips of equal widths of P1 and P2 are obtained. The process includes sheet depositing a magnetic layer, then depositing a sheet of gap material, and then depositing a sheet of another magnetic layer. This operation can be done either by a vacuum technique or by an electroplating process. If it is done by vacuum processing, all the three depositions can be done in one pumpdown. Since the sheet magnetic films are deposited, the demagnetizing field is very small, and a small orienting field is necessary unlike the large field required in the prior art.
    Type: Grant
    Filed: May 21, 1992
    Date of Patent: April 11, 1995
    Assignee: DAS Devices, Inc.
    Inventor: Shyam C. Das
  • Patent number: 5221422
    Abstract: A microlithographic process of fabricating electronic components, such as, for example, integrated circuit chips and thin film read/write heads for computer disk systems, in which a laser is used to etch features defined by a mask. The laser is selected whose radiation will be absorbed by the workpiece being etched, and the masking material is selected so as to be highly reflective of the laser radiation. The masking material is patterned in a conventional manner so as to expose the portions of the workpiece material to be etched. When the laser is directed to the workpiece, the laser radiation etches the portions of the workpiece not protected by the mask. A preferred process of scanning with a laser is disclosed. Etching may be improved if performed under a liquid transparent to the laser radiation.
    Type: Grant
    Filed: June 22, 1989
    Date of Patent: June 22, 1993
    Assignee: Digital Equipment Corporation
    Inventors: Shyam C. Das, Jamaluddin Khan
  • Patent number: 5159511
    Abstract: A read-write head comprising a magneto-resistive element and a conductor for producing a longitudinal magnetic bias field along said MR element. The conductor may also be arranged to produce a transverse magnetic bias field.
    Type: Grant
    Filed: June 29, 1990
    Date of Patent: October 27, 1992
    Assignee: Digital Equipment Corporation
    Inventor: Shyam C. Das
  • Patent number: 5111352
    Abstract: A magnetic recording head including a read pole disposed in a gap between a pair of write poles, and a sensor spaced away from the gap, the read pole adapted to conduct flux to the sensor, each write pole forming a respective cavity between itself and the read pole where the outside of at least one pole is tapered down toward the pole tip, the poles being closer together at their tips than they are near the sensor.
    Type: Grant
    Filed: June 22, 1989
    Date of Patent: May 5, 1992
    Assignee: Digital Equipment Corporation
    Inventors: Shyam C. Das, Michael L. Mallary
  • Patent number: 5081554
    Abstract: A combined transverse and longitudinal biasing conductor for MR element, and a thin film head including same.
    Type: Grant
    Filed: June 6, 1990
    Date of Patent: January 14, 1992
    Assignee: Digital Equipment Corporation
    Inventor: Shyam C. Das
  • Patent number: 5075956
    Abstract: A recording head includes at least one magnetic pole and magnetic side shields adjacent to the pole, the side shields disposed to shield the pole from adjacent tracks on a magnetic medium. Embodiments are disclosed for both longitudinal and vertical recording in monopole, two-pole, and three-pole heads, including inductive, MR and Hall-type read elements. A magnetic head capable of detecting flux from a target source among a group of sources, includes at least one magnetic pole and a magnetic shield, the shield providing to the pole 360.degree. of magnetic shielding against sensing by the pole of flux other than the target source. Also disclosed is an alternate flux return conductor being separated at the pole tip from the shield section by a non-magnetic insulation layer. A shielded magnetic head may have two outer magnetic poles, the two outer poles acting as the magnetic shield for a center pole, whereby the outer poles can be used for writing and the center pole can be used for reading.
    Type: Grant
    Filed: April 24, 1990
    Date of Patent: December 31, 1991
    Assignee: Digital Equipment Corporation
    Inventor: Shyam C. Das
  • Patent number: 4985985
    Abstract: A new read/write head for use in a mass storage device in a digital data processing system. The head is a thin-film head having a solenoidal coil around one or both of the pole pieces. Sets of planar conductive traces are formed on planar layers of insulating material on opposing sides of a pole piece, with vias connecting the ends of selected traces to thereby form a solenoidal coil around the pole piece.
    Type: Grant
    Filed: July 1, 1987
    Date of Patent: January 22, 1991
    Assignee: Digital Equipment Corporation
    Inventor: Shyam C. Das
  • Patent number: 4935832
    Abstract: Side shields are provided adjacent to the magnetic poles of recording heads. The side shields are used for read and write operations for both longitudinal and vertical recording. During read, the side shields intercept flux from adjacent tracks and shunts it around the sensor to magnetic ground. During write, side shields contain the write field of the head so that it does not corrupt the data on adjacent tracks. Embodiments are disclosed for both longitudinal and perpendicular or vertical recording.
    Type: Grant
    Filed: March 16, 1988
    Date of Patent: June 19, 1990
    Assignee: Digital Equipment Corporation
    Inventors: Shyam C. Das, Michael L. Mallary
  • Patent number: 4900650
    Abstract: The mask through which the pole piece is deposited by through mask plating has a yoke region, a narrower pole tip region and a bulb region adjacent the pole tip region. The bulb region results in substantially uniform current density during the through mask plating which results in substantially uniform composition and thickness of the pole piece material across the pole piece. In particular, the composition difference between the pole tip and the yoke region is reduced from that according to prior art techniques. The combination of the composition uniformity and the different (than the prior art) stress distribution in the pole tip material results in favorable domain structure in the pole tip. The magnetic domains formed conduct flux by coherent rotation of the magnetization direction in the domains without changing the location of wall boundaries thereby reducing Barkhausen noise.
    Type: Grant
    Filed: May 12, 1988
    Date of Patent: February 13, 1990
    Assignee: Digital Equipment Corporation
    Inventor: Shyam C. Das
  • Patent number: 4885649
    Abstract: A read/write head for use in a magnetic storage device in a digital data processing system for writing data in the form of magnetic flux onto, and reading data from a spinning magnetic disk. The head has two magnetic pole pieces each with a yoke region which tapers to a pole tip and an energizable coil situated between the pole pieces in the yoke region for generating magnetic flux. One of the pole pieces has a slot in the yoke region, and a strip of magneto-resistive material is situated adjacent the slot. The magneto-resistive strip is adapted to be connected to sensing equipment which measures variations in the resistance of the magneto-resistive strip in response to the variations in the magnetic flux recorded on the media. Several slots may be formed in the pole pieces, and an elongated magneto-resistive strip may be situated adjacent the slots.
    Type: Grant
    Filed: October 4, 1988
    Date of Patent: December 5, 1989
    Assignee: Digital Equipment Corporation
    Inventor: Shyam C. Das
  • Patent number: RE33949
    Abstract: The present device provides a downstream magnetic shield which is integrally formed with a write pole section having a tip to make up a magnetic recording head. The shield and the write pole tip are located with small gap therebetween, so that magnetic flux which fringes from the magnetic write pole tip is intercepted by the shield. Accordingly such fringing flux does not pass through the recording medium, and hence if a data bit has been written into the recording medium its dipole identity will not be weakened by the fringing flux of a subsequent data bit being written into the magnetic recording medium. In addition, the magnetic recording medium is made up of a first layer of material having perpendicular uniaxial anisotropy and an underlying layer made of a material which has a low magnetic flux reluctance characteristic.
    Type: Grant
    Filed: November 7, 1990
    Date of Patent: June 2, 1992
    Assignee: Digital Equipment Corporation
    Inventors: Michael L. Mallary, Shyam C. Das