George Clifford

Author:

George Clifford

ISBN #:

0135947553

Author:

George Clifford

ISBN #:

0394481453

Author:

George F. Clifford

ISBN #:

0136028306

Author:

George E. Clifford

ISBN #:

0835928128

US Patent:

6820797, Nov 23, 2004

Filed:

Jan 27, 2003

Appl. No.:

10/352287

Inventors:

George M. Clifford - Los Altos Hills CA

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

B23K 3512

US Classification:

228246, 228194, 228245, 349153, 349155

Abstract:

Systems and methods for forming a seal between members of an assembly are disclosed. In one embodiment, a seal is formed between a first member and a second member by establishing within the members a bounded volume and creating within the bounded volume a pressure differential with respect to the ambient pressure outside the bounded volume. The pressure differential results in a uniformly applied clamping force to the members thereby creating a reliable seal. A sealing member (such as solder, epoxy, or other sealant) is positioned between the first and second members and the resulting assembly is mechanically positioned such that heat can then be applied to melt the solder. Concurrently, the pressure differential is created which allows the externally applied mechanical positioning to be relaxed while the members are being sealed together. This system and method can be used to create hermetic seals.

US Patent:

20010007170, Jul 12, 2001

Filed:

Feb 22, 2001

Appl. No.:

09/791903

Inventors:

Patricia Beck - Palo Alto CA, US
Paul Poorman - Meridian ID, US
George Clifford - Los Altos Hills CA, US
Richard Henze - San Carlos CA, US

International Classification:

G11B005/127
H04R031/00

US Classification:

029/603070, 029/603230

Abstract:

A batch fabrication technique is described that increases the manufacturing efficiency of servo write heads and also improves servo pattern definition for fine features, while reducing tape and head wear. Multiple heads are fabricated as a batch from one or more ferrite wafers. A nominally flat, large wafer surface and a contour suitable for uniform photoresist application and planar photolithography permit fine servo pattern definition. A rounded leading edge on the head creates an air bearing to reduce wear of the tape and of the head. Moreover, any head wear occurs at the leading edge rather than in the region of the head where the servo pattern is formed. The servo write head may have a substantially planar head surface. A leading edge is disposed adjacent to the head surface such that the tape contacts the leading edge before passing over the head surface. The leading edge is rounded to form an air bearing between the head surface and the tape. A rounded trailing edge may be disposed adjacent to the head surface such that the tape passes over the trailing edge after passing over the head surface. The head may be formed from an upper ferrite wafer having a non-magnetic spacer. Non-magnetic material is photolithographically defined to produce gaps above the spacer. The non-magnetic material may be photoresist, semiconductor materials, glass, metal or the like. The material may even be removed later to leave air gaps. The non-magnetic material forms a region where the field loops out to intersect the passing tape, thereby transferring a magnetic pattern to tape. Additionally, a lower ferrite wafer may be mated to the upper ferrite wafer to complete a magnetic circuit around the gaps. The upper or lower ferrite wafer may have a channel through which an inductive winding passes. Multiple heads may be formed through batch processing of the upper and lower ferrite wafers.

US Patent:

20020057524, May 16, 2002

Filed:

Jun 14, 2001

Appl. No.:

09/791969

Inventors:

Patricia Beck - Palo Alto CA, US
Paul Poorman - Meridian ID, US
George Clifford - Los Altos Hills CA, US
Richard Henze - San Carlos CA, US

International Classification:

G11B005/187

US Classification:

360/122000

Abstract:

A batch fabrication technique is described that increases the manufacturing efficiency of servo write heads and also improves servo pattern definition for fine features, while reducing tape and head wear. Multiple heads are fabricated as a batch from one or more ferrite wafers. A nominally flat, large wafer surface and a contour suitable for uniform photoresist application and planar photolithography permit fine servo pattern definition. A rounded leading edge on the head creates an air bearing to reduce wear of the tape and of the head. Moreover, any head wear occurs at the leading edge rather than in the region of the head where the servo pattern is formed. The servo write head may have a substantially planar head surface. A leading edge is disposed adjacent to the head surface such that the tape contacts the leading edge before passing over the head surface. The leading edge is rounded to form an air bearing between the head surface and the tape. A rounded trailing edge may be disposed adjacent to the head surface such that the tape passes over the trailing edge after passing over the head surface. The head may be formed from an upper ferrite wafer having a non-magnetic spacer. Non-magnetic material is photolithographically defined to produce gaps above the spacer. The non-magnetic material may be photoresist, semiconductor materials, glass, metal or the like. The material may even be removed later to leave air gaps. The non-magnetic material forms a region where the field loops out to intersect the passing tape, thereby transferring a magnetic pattern to tape. Additionally, a lower ferrite wafer may be mated to the upper ferrite wafer to complete a magnetic circuit around the gaps. The upper or lower ferrite wafer may have a channel through which an inductive winding passes. Multiple heads may be formed through batch processing of the upper and lower ferrite wafers.

US Patent:

20030030939, Feb 13, 2003

Filed:

Sep 27, 2002

Appl. No.:

10/256572

Inventors:

Patricia Beck - Palo Alto CA, US
Paul Poorman - Meridian ID, US
George Clifford - Los Altos Hills CA, US
Richard Henze - San Carlos CA, US

International Classification:

G11B005/265
G11B005/29
G11B005/127

US Classification:

360/121000, 360/122000, 029/603160, 029/603230

Abstract:

A batch fabrication technique is described that increases the manufacturing efficiency of servo write heads and also improves servo pattern definition for fine features, while reducing tape and head wear. Multiple heads are fabricated as a batch from one or more ferrite wafers. A nominally flat, large wafer surface and a contour suitable for uniform photoresist application and planar photolithography permit fine servo pattern definition. A rounded leading edge on the head creates an air bearing to reduce wear of the tape and of the head. Moreover, any head wear occurs at the leading edge rather than in the region of the head where the servo pattern is formed. The servo write head may have a substantially planar head surface. A leading edge is disposed adjacent to the head surface such that the tape contacts the leading edge before passing over the head surface. The leading edge is rounded to form an air bearing between the head surface and the tape. A rounded trailing edge may be disposed adjacent to the head surface such that the tape passes over the trailing edge after passing over the head surface. The head may be formed from an upper ferrite wafer having a non-magnetic spacer. Non-magnetic material is photolithographically defined to produce gaps above the spacer. The non-magnetic material may be photoresist, semiconductor materials, glass, metal or the like. The material may even be removed later to leave air gaps. The non-magnetic material forms a region where the field loops out to intersect the passing tape, thereby transferring a magnetic pattern to tape. Additionally, a lower ferrite wafer may be mated to the upper ferrite wafer to complete a magnetic circuit around the gaps. The upper or lower ferrite wafer may have a channel through which an inductive winding passes. Multiple heads may be formed through batch processing of the upper and lower ferrite wafers.

US Patent:

20030076510, Apr 24, 2003

Filed:

Oct 19, 2001

Appl. No.:

10/039599

Inventors:

George Clifford - Los Altos Hills CA, US
William Gong - Sunnyvale CA, US

International Classification:

G01B011/28

US Classification:

356/630000

Abstract:

The invention provides a system and method for reliably and accurately measuring the gap between two materials when the depth of gap is less than the smallest distance that an optical thickness gauge (OTG) is able to measure. The invention is practiced by forming a suitable slot (or a groove, channel, hole or other suitable deformation) having a precisely known depth in at least one material. The sum of the distance of the gap and the depth of the slot is at least equal to the smallest distance that the OTG can measure. The slot is positioned over the materials and under the OTG probe head such that a cavity is formed. The depth of the cavity is measured. Since the distance of the slot is known, the depth of the gap is determined by subtracting the known depth of the slot from the measured depth of the cavity.

US Patent:

20040099715, May 27, 2004

Filed:

Nov 27, 2002

Appl. No.:

10/306463

Inventors:

George Clifford - Los Altos Hills CA, US

International Classification:

B23K031/02

US Classification:

228/246000

Abstract:

Systems and methods for forming a seal between members of an assembly are disclosed. In one embodiment, a seal is formed between a first member and a second member by creating a near vacuum with respect to the members to be sealed. The vacuum results in a uniformly applied clamping force to the members thereby creating a reliable seal. A sealing member (such as solder) is positioned between first and second members and the resulting assembly is mechanically positioned such that heat can then be applied to melt the solder. Concurrently, a vacuum is created within the assembly, thereby allowing the externally applied mechanical pressure to be relaxed. The created vacuum allows the members to seal together without externally applied forces.

US Patent:

20040109257, Jun 10, 2004

Filed:

Nov 26, 2003

Appl. No.:

10/723757

Inventors:

Patricia Beck - Palo Alto CA, US
George Clifford - Los Altos Hills CA, US

International Classification:

G11B020/20
G11B005/584

US Classification:

360/076000, 360/077120

Abstract:

A device for precision alignment of a write element of a tape head to a transport direction of a media that is transported across the tape head is disclosed. The tape head includes at least one alignment element that is cofabricated with the write element so that both the write element and the alignment element have a fixed orientation with respect to a magnetic axis of the tape head. The alignment element and the write element can be fabricated on the tape head using standard microelectronic photolithographic processes. Preferably, the tape head includes a plurality of alignment elements. Those alignment elements are operative to write alignment transitions onto the media. The alignment transitions can be observed to determine if they are indicative of the write element having a predetermined orientation with respect to the transport direction. A read transducer can be used to generate signals from the alignment transitions and those signals can be analyzed to determine if the predetermined orientation of the write element has been achieved. The tape head can include horizontal and/or vertical elements for a gross visual alignment of the tape head to the media. The alignment transitions can be read by a data element of a separate data head. A signal from the data element can be used to adjust the azimuth of the data head with respect to a direction of transport. In servo writer applications where servo code is prerecorded on the media, the alignment transitions can be used to align the write elements of a servo write head to the transport direction of the media so that inter band skew between adjacent servo bands is significantly reduced.

US Patent:

20040165640, Aug 26, 2004

Filed:

Feb 25, 2003

Appl. No.:

10/374169

Inventors:

George Clifford - Los Altos Hills CA, US
Geraint Owen - Palo Alto CA, US

International Classification:

H01S003/10
H01S003/082
H01S003/08

US Classification:

372/097000, 372/020000

Abstract:

Adjustment of a tunable external-cavity laser is simplified by incorporating a mount that includes a base, a main body, a reflecting surface, a diffracting surface and a hinge coupling the main body to the base. The laser additionally includes a light source, a converging lens located to receive light from the light source, a tuning mirror and a pivoting arm on which the tuning mirror is mounted. The main body is bounded in part by two plane, external surfaces orthogonal to a common reference plane and angularly separated from one another by an angle. The reflecting surface has a spatial orientation defined by one of the external surfaces and is arranged to receive light from the lens. The diffracting surface has a spatial orientation defined by the other of the external surfaces, and diffracts light received from the reflecting surface towards the tuning mirror. The hinge is located opposite the angle and parallel to the reference plane.