Patents by Inventor Peter G. Bischoff

Peter G. Bischoff 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: 5973391
    Abstract: An interposer for assembly between an integrated circuit and a circuit panel includes an upper insulation layer and a plurality of upper contact pads arranged in a desired pattern in the upper insulation layer. A plurality of micro-devices are formed between the upper insulation layer and a bottom insulation layer having a plurality of lower contact pads arranged in a desired pattern. The upper and the lower contact pads are selectively and electrically interconnected via the micro-devices. The upper and the lower contact pads are overlaid with solder balls to provide the required electrical connection and mechanical coupling between the interposer, the integrated circuit, and the circuit panel.
    Type: Grant
    Filed: December 11, 1997
    Date of Patent: October 26, 1999
    Assignee: Read-Rite Corporation
    Inventors: Peter G. Bischoff, Ross W Stovall
  • Patent number: 5949627
    Abstract: A thin film magnetic head is fabricated having soft metal layers of 0.25 to 1 micron thickness disposed on each side of the first and second magnetic layers of Permalloy forming the magnetic yoke. The soft layers are formed between the ceramic substrate and the first Permalloy layer, between the first Permalloy layer and the insulation surrounding the electrical coil of the head, between the insulation and the second Permalloy layer, and between the second Permalloy layer and the insulating overcoat of the head. The soft metal has a coefficient of thermal expansion between that of the Permalloy and that of the ceramic substrate and insulation materials. In this way, stress buffers are provided to minimize the mismatch and thermal stress transfer between the Permalloy and the other materials of the adjacent layers, resulting in improved domain stability and a significant reduction in popcorn noise.
    Type: Grant
    Filed: February 19, 1993
    Date of Patent: September 7, 1999
    Assignee: Read-Rite Corporation
    Inventors: Edgar M. Williams, Peter G. Bischoff, Daniel A. Nepela
  • Patent number: 5886959
    Abstract: A thin-film coil for use in a flying magneto-optical data storage system is formed on an undercoat layer, and includes an underside and a conductor deposited on the undercoat layer. The conductor is covered by an insulation layer on which a yoke is formed for providing a path to a magnetic field generated by the conductor. The yoke is formed of three sections: an upper section, an intermediate section, and the tip. The yoke tip defines an optical opening and has its underside substantially flush with the underside of the undercoat layer for increasing the density of the magnetic field at a target distance from the coil. The yoke tip underside is defined by an inner edge that delineates the optical opening, and that is formed of two semi-circular sections and two linear sections tangential to the semi-circular sections. The yoke can optionally include an outer section that extends over the peripheral side of the insulation layer and that further extends in an enlarged toe section.
    Type: Grant
    Filed: February 4, 1998
    Date of Patent: March 23, 1999
    Assignees: Read-Rite Corporation, Quinta Corporation
    Inventors: Peter G. Bischoff, Yugang Wang
  • Patent number: 5452168
    Abstract: A thin film magnetic head is fabricated with a multiplicity of magnetic yokes that interact effectively with an electrical coil. The magnetic P1 and P2 pole sections of the yoke are very narrow and form closely spaced envelopes about the coil. The multiple yokes are inductively linked to the coil so as to provide an increased number of flux interactions for a given length of coil turn. With this magnetic head design, signal output is increased, thermal noise is reduced, and the signal-to-noise ratio is effectively improved.
    Type: Grant
    Filed: July 25, 1994
    Date of Patent: September 19, 1995
    Assignee: Read-Rite Corporation
    Inventors: Daniel A. Nepela, Shih-Cheng Cheng, Erich P. Valstyn, Edgar M. Williams, Peter G. Bischoff
  • Patent number: 5373408
    Abstract: A thin film magnetic head is fabricated with shaping magnetic thin films, preferably formed of Permalloy, which have a stepped configuration. The thin films are deposited between the insulation layer surrounding the electrical coil and below the second pole layer P2 to form a double yoke. The thin films have corners at the stepped areas which pin the domain sites so that the magnetization of the P2 layer is properly aligned, thereby improving the data signal that is being recorded.
    Type: Grant
    Filed: May 31, 1994
    Date of Patent: December 13, 1994
    Assignee: Read-Rite Corporation
    Inventors: Peter G. Bischoff, Hua-Ching Tong, Johnny C. Chen
  • Patent number: 5327310
    Abstract: A thin film magnetic head assembly useful for contact recording in a disk drive comprises an air bearing slider formed with only a single air bearing rail. The slider is substantially L-shaped having a leg portion on which a pedestal with an air bearing surface is provided. A wear pad is formed on the pedestal and encompasses the pole tips and transducing gap of the transducer. The wear pad makes contact with the magnetic disk during operation of the disk drive. The small area of the wear pad makes minimal contact with the surface of the magnetic disk so that frictional effects are significantly reduced thereby extending the wear life of the magnetic head. An alternative embodiment of a contact head slider uses a tripad design wherein the front pads fly relative to the disk and the rear pad which supports the transducer is in contact with the rotating disk during operation of a disk drive.
    Type: Grant
    Filed: June 25, 1992
    Date of Patent: July 5, 1994
    Assignee: Read-Rite Corporation
    Inventors: Peter G. Bischoff, Chak M. Leung, Stephen S. Murray
  • Patent number: 5312644
    Abstract: A thin-film magnetoresistive playback head having films providing magnetic shielding and magnetic bias. At least one of the magnetic shield layers is also conductive so that the functions of shielding and biasing are combined. Preferably, both shield layers are conductive. A multiple element channel head is disclosed in which the magnetic/conductive layers extend in series from one transducer section to the next, allowing a single bias current to bias all of the sections.
    Type: Grant
    Filed: September 17, 1993
    Date of Patent: May 17, 1994
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Theodore A. Schwarz, Peter G. Bischoff, Chak M. Leung, Johnny C. Chen, Pradeep Thayamballi
  • Patent number: 5311385
    Abstract: A thin-film magnetoresistive playback head having films providing magnetic shielding and magnetic bias. At least one of the magnetic shield layers is also conductive so that the functions of shielding and biasing are combined. Preferably, both shield layers are conductive. A multiple element channel head is disclosed in which the magnetic/conductive layers extend in series from one transducer section to the next, allowing a single bias current to bias all of the sections.
    Type: Grant
    Filed: December 18, 1991
    Date of Patent: May 10, 1994
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Theodore A. Schwarz, Peter G. Bischoff, Chak M. Leung, Johnny C. Chen, Pradeep Thayamballi
  • Patent number: 5255142
    Abstract: A thin film magnetic head is fabricated with a yoke structure, including P1 and P2 magnetic layers, having a width in the range of about 5 to 58 microns, preferably about 30 microns. The very narrow width minimizes popcorn noise, improves high frequency response and affords increased head circuit efficiency.
    Type: Grant
    Filed: April 19, 1993
    Date of Patent: October 19, 1993
    Assignee: Read-Rite Corp.
    Inventors: Edgar M. Williams, Peter G. Bischoff, Shin-ichi Akoh
  • Patent number: 5237476
    Abstract: A thin film tape head assembly is formed by depositing a multiplicity of thin film transducers on a ceramic wafer or substrate. The wafer is divided into head bars, each of which has one or more thin film transducers on its face. End sections and a cover bar are joined to the head bar to form a head bar subassembly. A flexible cable or electrical pins are provided between the end sections to enable electrical connection between the head circuit and external circuitry. By joining a number of head bar subassemblies, a multigap thin film tape head assembly is produced to serve as a read/write device.
    Type: Grant
    Filed: May 28, 1991
    Date of Patent: August 17, 1993
    Assignee: Read-Rite Corp.
    Inventors: Peter G. Bischoff, Carroll S. Gooden, Chak M. Leung
  • Patent number: 5173826
    Abstract: A thin film head assembly includes a coil structure having a thin coil layer that extends within and beyond the magnetic yoke area delineated between opposing magnetic pole pieces, and an additional coil layer formed as a step segment adjacent to the thin layer. The additional layer is spaced away from the pole pieces and the magnetic yoke area and provides a thickened coil area which affords a significant reduction in coil resistance.
    Type: Grant
    Filed: June 3, 1991
    Date of Patent: December 22, 1992
    Assignee: Read-Rite Corp.
    Inventor: Peter G. Bischoff
  • Patent number: 5117589
    Abstract: An adjustable transfer tool is used to compensate for row bow during lapping a bar or a row of magnetic head sliders. The adjustable transfer tool enables establishing uniform and substantially precise throat heights for a multiplicity of thin film transducers disposed on said sliders. To allow the desired adjustment, the transfer tool incorporates slot means by which the shape of the surface of the tool on which the bar of sliders is mounted can be modified so that the slider transducers assume a collinear array across its entire length for the lapping process. Adjustment is accomplished by manual means, such as by a screw or a tapered pipe plug, or by electrical means, such as a piezoelectric actuator, in conjunction with a computer or microprocessor.
    Type: Grant
    Filed: April 1, 1991
    Date of Patent: June 2, 1992
    Assignee: Read-Rite Corporation
    Inventors: Peter G. Bischoff, Robert A. Cole
  • Patent number: 4694368
    Abstract: A thin film magnetic head is made with a center-tapped coil structure formed of three layers of coils. The middle coil is configured to be bifilar. When recording data on a magnetic medium, current flows through one-half of the bifilar coil and through one adjacent coil to create positive transitions, and for negative transitions, current flows through the other half of the bifilar coil and through the other adjacent coil. When reading the data that is recorded on a magnetic medium, all turns of the entire coil configuration operate for transducing the data.
    Type: Grant
    Filed: January 10, 1986
    Date of Patent: September 15, 1987
    Assignee: Read-Rite Corporation
    Inventors: Peter G. Bischoff, David J. Rauch, Vincent D. Retort, John R. Osborne
  • Patent number: 4517616
    Abstract: The subject invention relates to the fabrication of metal oxide patterns on a substrate adapted for use with thin film magnetic heads. The metal oxide pattern has a precisely defined geometry including nearly vertical side walls, for minimizing read/write errors. In addition, a filler material formed from a non-magnetic, non-metallic compound is provided on the substrate in a pattern complimentary to the metal oxide pattern. In accordance with the subject invention, the top surface of the metal oxide pattern and the filler material are co-planar. By this arrangement, subsequent layers may be uniformly deposited without discontinuities. The subject method includes a plurality of distinct masking and etching steps in order to achieve the desired result.
    Type: Grant
    Filed: March 28, 1983
    Date of Patent: May 14, 1985
    Assignee: Memorex Corporation
    Inventor: Peter G. Bischoff
  • Patent number: 4454014
    Abstract: A method for fabricating a metallic pattern on a substrate is disclosed. The method consists of depositing an adhesive and/or plating base material on a substrate upon which a narrow self-supporting border of photoresist is applied. An anodic layer is then deposited and the photoresist removed. The adhesive and plating base material is etched in those areas previously covered by the photoresist and fresh photoresist applied to encapsulate those areas of the anodic layer which form the final pattern of interest. The unwanted anodic material is then etched and the photoresist removed.
    Type: Grant
    Filed: January 3, 1983
    Date of Patent: June 12, 1984
    Assignee: Memorex Corporation
    Inventor: Peter G. Bischoff
  • Patent number: 4436593
    Abstract: A method is disclosed for precisely aligning the pole tips of a thin film magnetic head. Two separate metallic layers, such as Permalloy (Ni-Fe alloy) are separated by a layer of insulating material such as silicon dioxide or AL.sub.2 O.sub.3 which will serve as the insulative spacer of the final magnetic head. A photo-resist is applied to the surface of the top metallic layer in an imagewise configuration to establish the shape of the top pole. The top pole is then etched and the photo-resist removed. The top electrode is then encapsulated with a protective metal and is used as a mask during the chemical etching of the insulative layer, the bottom electrode being used as an etch stop. This integral structure is then used as a mask during the chemical etching of the bottom electrode, resulting in pole tips which are precisely aligned.
    Type: Grant
    Filed: July 13, 1981
    Date of Patent: March 13, 1984
    Assignee: Memorex Corporation
    Inventors: John R. Osborne, Peter G. Bischoff
  • Patent number: 4391849
    Abstract: The subject invention relates to the fabrication of metal oxide patterns on a substrate adapted for use with thin film magnetic heads. The metal oxide pattern has a precisely defined geometry including nearly vertical side walls, for minimizing read/write errors. In addition, a filler material formed from a non-magnetic, non-metallic compound is provided on the substrate in a pattern complimentary to the metal oxide pattern. In accordance with the subject invention, the top surface of the metal oxide pattern and the filler material are co-planar. By this arrangement, subsequent layers may be uniformly deposited without discontinuities. The subject method includes a plurality of distinct masking and etching steps in order to achieve the desired result.
    Type: Grant
    Filed: April 12, 1982
    Date of Patent: July 5, 1983
    Assignee: Memorex Corporation
    Inventor: Peter G. Bischoff