Theodore B Schwarz

US Patent:

7283317, Oct 16, 2007

Filed:

Jan 30, 2004

Appl. No.:

10/768719

Inventors:

Matthew P. Dugas - St. Paul MN, US
Theodore A. Schwarz - Woodbury MN, US

Assignee:

Advanced Research Corporation - White Bear MN

International Classification:

G11B 5/09
G11B 15/18

US Classification:

360 48, 360 71

Abstract:

The present invention relates to direct current (“DC”) pre-erasing servo channels of a magnetic tape prior to writing servo data in a servo channel. The present invention particularly relates to those servo recordings which were written with a uni-polar current waveform. The DC pre-erase is performed using a uni-polar direct current of a polarity that is opposite to the polarity of the direct current used to write the servo data. This pre-erase may be done with one or more heads. Also, as will be described, the pre-erase of a servo channel and writing to a servo channel may be done by making two passes over a single head or by using two or more heads to perform both steps. Also, it is within the scope of the present invention to have the heads mounted on a single mount or have the heads on separate mounts and on separate tape decks.

US Patent:

7301716, Nov 27, 2007

Filed:

Mar 2, 2004

Appl. No.:

10/791675

Inventors:

Matthew P. Dugas - St. Paul MN, US
Theodore A. Schwarz - Woodbury MN, US

Assignee:

Advanced Research Corporation - White Bear MN

International Classification:

G11B 5/09
G11B 21/02

US Classification:

360 48, 360 7712, 360 75

Abstract:

The present invention relates to a method of synthesizing the slanted transitions in a time based servo pattern using servo write gaps that are perpendicular to the tape motion. The present invention particularly relates to a method of writing a servo pattern on magnetic tape so as to minimize errors in the servo pattern. The slanted transitions in a time-based servo pattern are synthesized using servo write gaps that are perpendicular to the tape motion. The slanted portions of the write gaps are synthesized by a series of short segmented vertical and horizontal segments. In so minimizing errors, distortion in the reading and/or writing of the data tracks can be prevented.

US Patent:

7450341, Nov 11, 2008

Filed:

May 3, 2005

Appl. No.:

11/120640

Inventors:

Matthew P. Dugas - St. Paul MN, US
Theodore A. Schwarz - Woodbury MN, US

Assignee:

Advanced Research Corporation - White Bear MN

International Classification:

G11B 21/02
G11B 5/584

US Classification:

360121, 360 7712

Abstract:

An arbitrary gap thin film magnetic recording head is fabricated by forming a substrate based on traditional vertical planar thin film head wafer technology which is designed to produce an integrated subgap and subpole substrate structure. The recording head includes a pair of magnetically permeable thin film subpoles, separated by a low permeability subgap structure. An electrically conductive coil may be embedded, in part, within the subgap structure. Thus, the subpoles and subgap structure form part of a magnetic circuit. A highly permeable magnetic surface film spans from one subpole to the other having one or more arbitrary gap patterns. That is, a surface thin film is deposited and patterned on the tape bearing surface of the head to optimize various element configurations, gap patterns and head-to-tape medium contact.

US Patent:

7511907, Mar 31, 2009

Filed:

Feb 17, 2005

Appl. No.:

11/060627

Inventors:

Matthew P. Dugas - St. Paul MN, US
Theodore A. Schwarz - Woodbury MN, US

Assignee:

Advanced Research Corporation - White Bear MN

International Classification:

G11B 5/09
G11B 21/02
G11B 5/584

US Classification:

360 48, 360 75, 360 7712, 360121

Abstract:

The present invention relates to apparatuses and methods used in manufacturing magnetic tape. More specifically, the present invention relates to a method of writing a servo pattern on magnetic tape so as to minimize errors in the servo pattern, the heads used to write such servo data, and the magnetic tape manufactured with such heads. Errors in the servo pattern may be minimized by synthesizing the slanted transitions in a time based servo pattern using servo write gaps that are perpendicular to the tape motion. In so minimizing errors, distortion in the reading and/or writing of the data tracks can be prevented.

US Patent:

7576949, Aug 18, 2009

Filed:

Aug 13, 2007

Appl. No.:

11/838006

Inventors:

Matthew P. Dugas - St. Paul MN, US
Theodore A. Schwarz - Woodbury MN, US

Assignee:

Advanced Research Corporation - White Bear Lake MN

International Classification:

G11B 5/127
G11B 5/265

US Classification:

360118, 360121

Abstract:

The present invention relates to direct current (“DC”) pre-erasing servo channels of a magnetic tape prior to writing servo data in a servo channel. The present invention particularly relates to those servo recordings which were written with a uni-polar current waveform. The DC pre-erase is performed using a uni-polar direct current of a polarity that is opposite to the polarity of the direct current used to write the servo data. This pre-erase may be done with one or more heads. Also, as will be described, the pre-erase of a servo channel and writing to a servo channel may be done by making two passes over a single head or by using two or more heads to perform both steps. Also, it is within the scope of the present invention to have the heads mounted on a single mount or have the heads on separate mounts and on separate tape decks.

US Patent:

7710675, May 4, 2010

Filed:

Nov 14, 2008

Appl. No.:

12/271203

Inventors:

Matthew P. Dugas - St. Paul MN, US
Theodore A. Schwarz - Woodbury MN, US

Assignee:

Advanced Research Corporation - White Bear MN

International Classification:

G11B 5/09
G11B 15/18

US Classification:

360 48, 360 71

Abstract:

The present invention relates to direct current (“DC”) pre-erasing servo channels of a magnetic tape prior to writing servo data in a servo channel. The present invention particularly relates to those servo recordings which were written with a uni-polar current waveform. The DC pre-erase is performed using a uni-polar direct current of a polarity that is opposite to the polarity of the direct current used to write the servo data. This pre-erase may be done with one or more heads. Also, as will be described, the pre-erase of a servo channel and writing to a servo channel may be done by making two passes over a single head or by using two or more heads to perform both steps. Also, it is within the scope of the present invention to have the heads mounted on a single mount or have the heads on separate mounts and on separate tape decks.

US Patent:

8416525, Apr 9, 2013

Filed:

Feb 23, 2011

Appl. No.:

13/032754

Inventors:

Theodore A. Schwarz - Woodbury MN, US
Matthew P. Dugas - St. Paul MN, US

Assignee:

Advanced Research Corporation - White Bear Lake MN

International Classification:

G11B 5/584
G11B 21/02

US Classification:

360121, 360 7712

Abstract:

A method of formatting magnetic media includes providing an integrated thin film magnetic recording head having a recording element. The recording element includes first and second magnetically permeable thin film subpole members separated by a substantially low permeability subgap member. An integrated electrically conductive coil structure is embedded in part within the subgap member and in part in-between the first and second subpole members. The recording element also includes a magnetically permeable thin film layer spanning from at least the first subpole member to the second subpole member and including one or more arbitrary recording gap patterns. The direction of film growth of the magnetically permeable thin film layer is substantially orthogonal to the direction of thin film growth of the first and second magnetically permeable thin film subpole members. The method includes passing magnetic media over the magnetic recording head to format the magnetic media.

US Patent:

20090147399, Jun 11, 2009

Filed:

Nov 10, 2008

Appl. No.:

12/268076

Inventors:

Matthew P. Dugas - St. Paul MN, US
Theodore A. Schwarz - Woodbury MN, US

International Classification:

G11B 5/33
G11B 5/78

US Classification:

360121, 360134, G9B 5104, G9B 5291

Abstract:

An arbitrary gap thin film magnetic recording head is fabricated by forming a substrate based on traditional vertical planar thin film head wafer technology which is designed to produce an integrated subgap and subpole substrate structure. The wafer is then processed into row bars to reveal, in a plane parallel to the transducing direction of the medium, the subgap and subpoles at the surface of the row bar and to bring the structure to a certain coil depth or gap depth. A flat or cylindrical contour may be utilized.This thin film subgap row bar is taken through a film deposition or growth process that deposits the magnetic film on a plane perpendicular to the wafer plane, horizontal planar processing, forming a surface film recording head where an arbitrary gap structure can be made in-between the subpoles and generally directly on top of the subgap. The surface thin film is deposited and patterned on the tape bearing surface of the head to optimize various element configurations, gap patterns and head-to-tape medium contact.An arbitrary gap thin film magnetic recording head is manufactured using two major thin film processing planes, one orthogonal to the other, the first major plane is wafer level and the second major plane is sub-wafer level and perpendicular to the first. The first major plane of processing defines the magnetically active substrate including coils, subgap and subpole members. The second major plane of processing defines the surface film which transmits the flux from the subpoles to the gap features contained in the surface film.This resulting structure is a recording head that is wired to the servo system electronics and will format the tape with the arbitrary gap pattern.