← Back to Patent Explorer
US5049848A Expired / Lapsed US ⏱️ 0.0 years remaining

High field strength magnet, preferably having remote shimming of field

Assignee: Individual
•
Filing: 1989-11-28
•
Granted: 1991-09-17
•
Expires: 2009-11-28
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A magnet configuration particularly suited for MRI imaging in mammography is disclosed. The magnetic structure 50 has a rectangular shaped magnet with at least two parallel magnetic sources 5,6 connected by a ferromagnetic core flux path defining an air gap for imaging. A remote shimming C-shaped magnetic source is preferably used to decrease the front edge fringe effect of the magnetic structure 50 to create a relatively homogeneous field in the air gap beginning at the front edge for effective imaging.

Inventors

  • 👤 Yuly M. Pulyer

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 22:33
CPC Classifications
H; H01; H01F; H01F7/00; H01F7/02; H01F7/0273; H01F7/0278; G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/38; G01R33/383; G01R33/387; G01R33/3875

Claims Analysis

Total Claims: 23
Claim 1
Independent Claim 181 words
A magnet configuration comprising, in combination, a primary magnet structure and a secondary magnet structure capable of providing substantial field homogeneity from the edge of the primary magnet structure facing the secondary magnet structure; said primary magnet structure comprising a generally rectangular structure in the ZX plane having two parallel magnetic flux sources with a first upper ferromagnetic flux guiding core section ridging the tops of the sources and a first lower ferromagnetic core flux guiding core section bridging the bottom of the sources thereby defining a volumetric air gap between the sources and the flux guiding core sections; said secondary magnetic structure comprising a generally C-shaped ferromagnetic core section having a magnetic source, the C-shaped core section being positioned relative to the primary magnetic structure with the ends of the C-shaped core section directed toward the volumetric air gap, the strength of the magnetic sources being predetermined to define a relatively homogeneous magnetic field in the volumetric air gap beginning at the edge of the primary magnetic structure closest to the C-shaped core section and extending in the ZY plane.
Claim 2
Dependent Claim 181 words
A magnet configuration comprising, in combination, a primary magnet structure and a secondary magnet structure capable of providing substantial field homogeneity from the edge of the primary magnet structure facing the secondary magnet structure; said primary magnet structure comprising a generally rectangular structure in the ZX plane having two parallel magnetic flux sources with a first upper ferromagnetic flux guiding core section ridging the tops of the sources and a first lower ferromagnetic core flux guiding core section bridging the bottom of the sources thereby defining a volumetric air gap between the sources and the flux guiding core sections; said secondary magnetic structure comprising a generally C-shaped ferromagnetic core section having a magnetic source, the C-shaped core section being positioned relative to the primary magnetic structure with the ends of the C-shaped core section directed toward the volumetric air gap, the strength of the magnetic sources being predetermined to define a relatively homogeneous magnetic field in the volumetric air gap beginning at the edge of the primary magnetic structure closest to the C-shaped core section and extending in the ZY plane.
Claim 3
Dependent Claim 34 words
The magnet configuration of claim 1 wherein the first upper flux guiding core section is M-shaped to lesson the dimension of the air gap between the upper and lower core sections near their center.
Claim 4
Dependent Claim 51 words
The magnet configuration of claim 2 wherein the M-shaped upper core section comprises two symmetrical excitation coils wound around the core section; both coils having an equal M-shaped copper flux guiding core section comprises two symnmetrical excitation coils wound around the core section, both coils having an equal number of turns.
Claim 5
Dependent Claim 52 words
The magnet configuration of claim 3 wherein the M-shaped upper core section further comprises two symmetrical excitation coils wound around the core section; both coils having an equal M-shaped copper flux guiding core section comprises two symnmetrical excitation coils wound around the core section, both coils having an equal number of turns.
Claim 6
Dependent Claim 34 words
The magnet configuration of claim 2 wherein the first upper flux guiding core section is M-shaped to lesson the dimension of the air gap between the upper and lower core sections near their center.
Claim 7
Dependent Claim 199 words
The magnet configuration of claim 1, wherein said primary magnetic structure further comprises a third parallel magnetic source and a flux path extending in the ZY plane defining a T-shaped structure extending away from the C-shaped secondary magnetic structure in the Y direction, the flux path being defined by a second upper ferrogmagnetic flux guiding core section extending perpendicular to the first upper flux guiding core section and a second lower flux guiding core section extending perpendicular to the first lower flux guiding core section; one end of the second upper flux guiding core section contacting the top of the third parallel magnetic source with the other end of the second upper flux guiding core section being contiguous to the first upper flux guiding core section and overlapping the volumetric air gap, one end of the second lower flux guiding core section contacting the bottom of the third magnetic source with the other end of the second lower flux guiding core section being contingent to the first lower flux guiding core section and overlapping the volumetric air gap, the flux from the third parallel magnetic source thereby summing with that of the other sources across the volumetric air gap.
Claim 8
Dependent Claim 63 words
The magnet configuration of claim 6 wherein the second upper flux guiding core section comprises two branch core sections, one branch section overlapping and contacting the central portion of the upper surface of the first upper flux guiding core section and the second branch section overlapping and contacting the central portion of the lower surface of the fist upper flux guiding core section.
Claim 9
Dependent Claim 18 words
The magnet configuration of claim 7 wherein each branch core section has an excitation coil wound around it.
Claim 10
Dependent Claim 90 words
The magnet configuration of claim 7 wherein the first upper flux guiding core section is M-shaped to lesson the dimension of the air gap between the first upper and first lower flux guiding core sections for s symmetrical portion near their center and the second upper and second lower flux guiding core sections defining the flux path from the third parallel magnetic source are contiguous to and overlap the first upper and first lower flux guiding core sections at the central portion where the air gap dimension has been decreased.
Claim 11
Dependent Claim 23 words
The magnet configuration of claim 6 wherein the two parallel magnetic sources and the third parallel magnetic source are mutually oriented permanent magnets.
Claim 12
Dependent Claim 18 words
The magnet configuration of claim 6 wherein each of the parallel magnetic sources comprises a mutually oriented electromagnetic.
Claim 13
Dependent Claim 20 words
The magnet configuration of claim 1, wherein the C-shaped core section further comprises a shimming excitation coil wound around it.
Claim 14
Dependent Claim 38 words
The magnetic configuration of claim 1, wherein the C-shaped core section further comprises two excitation coils wound around the core symmetrically disposed relative to the ends of the C-shaped core, both coils having an equal number of turns.
Claim 15
Dependent Claim 371 words
A magnet configuration comprising a primary magnet structure and a secondary magnet structure capable of providing substantial field homogeneity from the edge of the primary magnet structure facing the secondary magnet structure; said primary magnet structure comprising a generally T-shaped structure comprising two components: a first component having a rectangular structure in the ZX plane having two parallel magnetic flux sources with a first upper ferromagnetic flux guiding core section bridging the tops of the sources and a first lower ferromagnetic flux guiding core section bridging the bottom of the sources thereby defining a volumetric air gap between the sources and the flux guiding core sections; and a second component having a third parallel magnetic source and a flux path extending in the ZY plane defining a T-shaped structure extending away from the C-shaped secondary magnetic structure, in the Y direction, the flux path being defined by a second upper ferromagnetic flux guiding core section extending perpendicular to the first upper flux guiding core section and a second lower flux guiding core section extending perpendicular to the first lower flux guiding core section; one end of the second upper flux guiding core section contacting the top of the third parallel magnetic source with the other end of the second upper flux guiding core section being contiguous to the first upper flux guiding core section and overlapping the volumetric air gap, one end of the second lower flux guiding core section contacting the bottom of the third magnetic source with the other end of the second lower flux guiding core section being contiguous to the first lower flux guiding core section and overlapping the volumetric air gap, the flux from the parallel magnetic sources thereby summing across the volumetric air gap; said secondary magnetic structure comprising a generally C-shaped ferromagnetic core section having a magnetic source, the C-shaped core section being positioned relative to the primary magnetic structure with the ends of the C-shaped core section directed toward the volumetric air gap, the strength of the magnetic sources being predetermined to define a relatively homogeneous magnetic field in the volumetric air gap beginning at the edge of the primary magnetic structure closest to the C-shaped core section and extending the ZY plane.
Claim 16
Dependent Claim 371 words
A magnet configuration comprising a primary magnet structure and a secondary magnet structure capable of providing substantial field homogeneity from the edge of the primary magnet structure facing the secondary magnet structure; said primary magnet structure comprising a generally T-shaped structure comprising two components: a first component having a rectangular structure in the ZX plane having two parallel magnetic flux sources with a first upper ferromagnetic flux guiding core section bridging the tops of the sources and a first lower ferromagnetic flux guiding core section bridging the bottom of the sources thereby defining a volumetric air gap between the sources and the flux guiding core sections; and a second component having a third parallel magnetic source and a flux path extending in the ZY plane defining a T-shaped structure extending away from the C-shaped secondary magnetic structure, in the Y direction, the flux path being defined by a second upper ferromagnetic flux guiding core section extending perpendicular to the first upper flux guiding core section and a second lower flux guiding core section extending perpendicular to the first lower flux guiding core section; one end of the second upper flux guiding core section contacting the top of the third parallel magnetic source with the other end of the second upper flux guiding core section being contiguous to the first upper flux guiding core section and overlapping the volumetric air gap, one end of the second lower flux guiding core section contacting the bottom of the third magnetic source with the other end of the second lower flux guiding core section being contiguous to the first lower flux guiding core section and overlapping the volumetric air gap, the flux from the parallel magnetic sources thereby summing across the volumetric air gap; said secondary magnetic structure comprising a generally C-shaped ferromagnetic core section having a magnetic source, the C-shaped core section being positioned relative to the primary magnetic structure with the ends of the C-shaped core section directed toward the volumetric air gap, the strength of the magnetic sources being predetermined to define a relatively homogeneous magnetic field in the volumetric air gap beginning at the edge of the primary magnetic structure closest to the C-shaped core section and extending the ZY plane.
Claim 17
Dependent Claim 63 words
The magnet configuration of claim 14 wherein the second upper flux guiding core section comprises two branch core section, one branch section overlapping and contacting the central portion of the upper surface of the first upper flux guiding core section and the second branch section overlapping and contacting the central portion of the lower surface of the fist upper flux guiding core section.
Claim 18
Dependent Claim 91 words
The magnet configuration of claim 15 wherein the first upper flux guiding core section is M-shaped to descrease the dimension of the air gap between the first upper and first lower flux guiding core sections for a symmetrical portion near their center and the second upper and second lower flux guiding core sections defining the flux path from the third parallel magnetic source are contiguous to and overlap the first upper and first lower flux guiding core sections, respectively, at the central portion where the air gap dimension has been decreased.
Claim 19
Dependent Claim 23 words
The magnet configuration of claim 14 wherein the two parallel magnetic sources and the third parallel magnetic source are mutually oriented permanent magnets.
Claim 20
Dependent Claim 16 words
The magnet configuration of claim 14 wherein the parallel magnetic sources are each mutually oriented electromagnets.
Claim 21
Dependent Claim 37 words
The magnet configuration of claim 14 wherein the C-shaped core section further comprises two excitation coils wound around and symmetrically disposed relative to the ends of the C-shaped core, both coils having an equal number of turns.
Claim 22
Dependent Claim 241 words
A T-shaped magnet comprising two components: the first component having a rectangular structure in the ZX plane having two parallel magnetic flux sources with a first upper ferromagnetic flux guiding core section bridging the tops of the sources and a first lower ferromagnetic flux guiding core section ridging the bottom of the sources thereby defining a volumetric air gap between the sources and the flux guiding core sections; a second component having a third parallel magnetic source and a flux path extending the XY plane defining a T-shaped structure extending in the Y direction, the flux path being defined by a second upper ferromagnetic flux guiding core section extending perpendicular to the first upper flux guiding core section and a second lower flux guiding core section extending perpendicular to the first lower flux guiding core section; one end of the second upper flux guiding core section contacting the top of the third parallel magnetic source with the other end of the second upper flux guiding core section being contiguous to the first upper core section and overlapping the volumetric air gap, one end of the second lower flux guiding core section contacting the bottom of the third magnetic source with the other end of the second lower flux guiding core section being contiguous to the first lower flux guiding core section and overlapping the volumetric air gap, the flux from the parallel magnetic sources thereby summing across the volumetric air gap.
Claim 23
Dependent Claim 241 words
A T-shaped magnet comprising two components: the first component having a rectangular structure in the ZX plane having two parallel magnetic flux sources with a first upper ferromagnetic flux guiding core section bridging the tops of the sources and a first lower ferromagnetic flux guiding core section ridging the bottom of the sources thereby defining a volumetric air gap between the sources and the flux guiding core sections; a second component having a third parallel magnetic source and a flux path extending the XY plane defining a T-shaped structure extending in the Y direction, the flux path being defined by a second upper ferromagnetic flux guiding core section extending perpendicular to the first upper flux guiding core section and a second lower flux guiding core section extending perpendicular to the first lower flux guiding core section; one end of the second upper flux guiding core section contacting the top of the third parallel magnetic source with the other end of the second upper flux guiding core section being contiguous to the first upper core section and overlapping the volumetric air gap, one end of the second lower flux guiding core section contacting the bottom of the third magnetic source with the other end of the second lower flux guiding core section being contiguous to the first lower flux guiding core section and overlapping the volumetric air gap, the flux from the parallel magnetic sources thereby summing across the volumetric air gap.

References Cited (Backward Citations)

US3898599A Cited
US4679022A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1994-09-16 1995-03-18 1995-09-17 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1998-09-16 1999-03-18 1999-09-17 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2002-09-16 2003-03-18 2003-09-17 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag