US4631481A
Expired / Lapsed
US
⏱️ 0.0 years remaining
N.M.R. shims
Assignee: Philips Design Ltd
•
Filing: 1985-01-24
•
Granted: 1986-12-23
•
Expires: 2005-01-24
Abstract
Abstract A magnetic shim for an N.M.R. apparatus comprises a deformable body (particularly a flexible sheet) of electrically insulating material (e.g. P.V.C.) within which magnetic material (e.g. γ-ferric oxide or barium ferrite) is dispersed. The shim may easily be attached (e.g. by an adhesive backing layer) to an inside wall of the apparatus and may suitably be cut to size until suitable magnetic compensation is achieved by trial and error. The nature of the compensation effected by the shim may be altered by employing different magnetic materials dispersed within the non-conducting material and/or by varying their concentration.
Inventors
- 👤 Ian R. Young
- 👤 Philip R. Evans
- 👤 Peter A. Luker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:56
CPC Classifications
H; H05; H05K; H05K9/00; G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/38; G01R33/387; G01R33/3873; Y; Y10; Y10T; Y10T428/00; Y10T428/28
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
47 words
A method of reducing magnetic field inhomogeneities in N.M.R. apparatus, said method comprising the steps of cutting to size a deformable substantially non-electrically conducting body incorporating dispersed magnetic material but containing substantially no hydrogen nuclei and applying said body to a supporting surface of the N.M.R. apparatus.
Claim 2
Independent Claim
47 words
A method of reducing magnetic field inhomogeneities in N.M.R. apparatus, said method comprising the steps of cutting to size a deformable substantially non-electrically conducting body incorporating dispersed magnetic material but containing substantially no hydrogen nuclei and applying said body to a supporting surface of the N.M.R. apparatus.
Claim 3
Dependent Claim
23 words
A method according to claim 1 wherein at least one of said steps is repeated until compensation is achieved by trial and error.
Claim 4
Dependent Claim
17 words
A method according to claim 1 wherein said body is in the form of a flexible sheet.
Claim 5
Dependent Claim
14 words
A method according to claim 3 wherein said sheet incorporates an adhesive backing layer.
Claim 6
Dependent Claim
18 words
A method according to claim 1 wherein said magnetic material is saturated in use of said N.M.R. apparatus.
Claim 7
Dependent Claim
37 words
A method as claimed in claim 1 of reducing inhomogeneities in the gradient fields of magnetic coils in N.M.R. imaging apparatus, wherein said magnetic material exhibits a substantially linear magnetisation curve in use of said N.M.R. apparatus.
References Cited (Backward Citations)
GB1073567A
Cited
GB1057348A
Cited
GB1226181A
Cited
GB1227073A
Cited
US3598647A
Cited
US3569823A
Cited
GB1305768A
Cited
GB1339791A
Cited
GB1362720A
Cited
GB1330982A
Cited
GB1413884A
Cited
US4110236A
Cited
GB1531587A
Cited
DE2855134A1
Cited
FR2463490A1
Cited
JPS56104057A
Cited
EP0067933A1
Cited
EP0080160A1
Cited
GB2134128A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-12-22 | 1990-06-23 | 1990-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-22 | 1994-06-23 | 1994-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-22 | 1998-06-23 | 1998-12-23 | $7700.00 | Window Closed / Lapsed |