US3922547A
Expired / Lapsed
US
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Virtual electrode imaging chamber
Assignee: ELSCINT IMAGING Inc
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Filing: 1974-12-06
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Granted: 1975-11-25
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Expires: 1994-12-06
Abstract
Abstract An imaging chamber for an x-ray system using a dielectric or other suitable receptor of a latent electrostatic image in the gap between electrodes. A chamber with substantially planar electrodes, either flat or slightly cylindrical, with each electrode having a dielectric substrate with low conductivity surface at the gap with a plurality of spaced conductors thereon for connection to a voltage divider to produce electrostatic potentials at the gap surfaces the same as the electrostatic potentials of concentric spherical metal electrodes.
Inventors
- 👤 Andrew P Proudian
- 👤 Murray S Welkowsky
- 👤 Steven A Wright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:17
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/054; G03G15/0545
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
156 words
In an imaging chamber for an x-ray system, the combination of: first and second substantially planar electrodes; means for mounting said electrodes in the chamber in spaced relation defining a gap therebetween; each of said electrodes having an electrical insulating substrate with a low conductivity surface at said gap and means defining a plurality of spaced locations along the surface; means for connecting a first voltage source to said first electrode providing defined voltages between said spaced locations of said first electrode; means for connecting a second voltage source to said second electrode providing defined voltages between said spaced locations of said second electrode; and means for connecting a third voltage source between said first and second electrodes for maintaining along said surfaces of said electrodes, electrostatic potentials substantially corresponding to the electrostatic potentials for concentric spherical metal electrodes so that the extensions of the electric field lines in said gap converge substantially to a point.
Claim 2
Dependent Claim
156 words
In an imaging chamber for an x-ray system, the combination of: first and second substantially planar electrodes; means for mounting said electrodes in the chamber in spaced relation defining a gap therebetween; each of said electrodes having an electrical insulating substrate with a low conductivity surface at said gap and means defining a plurality of spaced locations along the surface; means for connecting a first voltage source to said first electrode providing defined voltages between said spaced locations of said first electrode; means for connecting a second voltage source to said second electrode providing defined voltages between said spaced locations of said second electrode; and means for connecting a third voltage source between said first and second electrodes for maintaining along said surfaces of said electrodes, electrostatic potentials substantially corresponding to the electrostatic potentials for concentric spherical metal electrodes so that the extensions of the electric field lines in said gap converge substantially to a point.
Claim 3
Dependent Claim
25 words
An imaging chamber as defined in claim 1 wherein said electrodes have flat parallel gap surfaces and said spaced locations are concentric with each other.
Claim 4
Dependent Claim
25 words
An imaging chamber as defined in claim 1 wherein said electrodes have concentric cylindrical gap surfaces and said spaced locations are parallel to each other.
Claim 5
Dependent Claim
21 words
An imaging chamber as defined in claim 1 wherein said means defining spaced locations comprise electrical conductors on said insulating substrates.
Claim 6
Dependent Claim
27 words
An imaging chamber as defined in claim 4 wherein said electrodes have flat parallel gap surfaces and said conductors on each electrode are concentric with each other.
Claim 7
Dependent Claim
26 words
An imaging chamber as defined inclaim 4 wherein said electrodes have concentric cylindrical gap surfaces and said conductors on each electrode are parallel to each other.
Claim 8
Dependent Claim
36 words
An imaging chamber as defined in claim 1 wherein each of said electrodes includes a dielectric sheet substrate with a plurality of spaced conductors on the gap surface thereof for connection to the corresponding voltage source.
Claim 9
Dependent Claim
51 words
An imaging chamber as defined in claim 1 wherein each of said electrodes includes a dielectric sheet substrate with a plurality of spaced conductors on the gap surface thereof, additional conductors on the opposite surface thereof for connection to the corresponding voltage source, and interconnections through the sheet between predetermined conductors.
Claim 10
Dependent Claim
56 words
An imaging chamber as defined in claim 1 wherein each of said electrodes includes: a dielectric sheet substrate; a plurality of spaced electrical conductors on the gap surface of said dielectric sheet for connection to the corresponding voltage source; and a low conductivity layer of substantially constant resistivity and thickness on said substrate over said conductors.
Claim 11
Dependent Claim
28 words
An imaging chamber as defined in claim 9 wherein each of said layers has a surface resistivity in the range of about 106 to 109 ohms per square.
Claim 12
Dependent Claim
51 words
An imaging chamber as defined in claim 1 wherein said means defining spaced locations comprise electrical conductors at said electrode surfaces, and each of said means for connecting said first and second voltage sources includes a voltage divider with points along the divider connected to the conductors of the corresponding electrode.
Claim 13
Dependent Claim
29 words
An imaging chamber as defined in claim 11 with said means for connecting said third voltage source providing said connection between corresponding conductors of said first and second electrodes.
Claim 14
Dependent Claim
49 words
An imaging chamber as defined in claim 1 wherein each of said first and second voltage sources provides an electrode current and said third voltage source provides a gap current, with the relative magnitudes of said sources such that the electrode current is substantially greater than the gap current.
Claim 15
Dependent Claim
21 words
An imaging chamber as defined in claim 13 wherein the electrode current is at least about five times the gap current.
Claim 16
Dependent Claim
19 words
An imaging chamber as defined in claim 1 including a first resistance connected in parallel with said first electrode.
Claim 17
Dependent Claim
19 words
An imaging chamber as defined in claim 15 including a second resistance connected in parallel with said second electrode.
Claim 18
Dependent Claim
47 words
An imaging chamber as defined in claim 1 wherein each of said electrode low conductivity surfaces is formed of a plurality of side-by-side sections, with adjacent sections of different and substantially uniform conductivities, with the section conductivity decreasing from the center to the edge of the electrode.
Claim 19
Dependent Claim
24 words
An imaging chamber as defined in claim 17 wherein said electrodes have flat parallel gap surfaces and said sections are concentric with each other.
Claim 20
Dependent Claim
24 words
An imaging chamber as defined in claim 17 wherein said electrodes have concentric cylindrical gap surfaces and said sections are parallel to each other.
Claim 21
Dependent Claim
100 words
An imaging chamber as defined in claim 1 wherein said first electrode includes: a dielectric sheet substrate; a plurality of spaced electrical conductors on the gap surface of said dielectric sheet for connection to said first voltage source; a first low conductivity layer of substantially constant resistivity and thickness on said substrate over said conductors; and a second low conductivity layer of substantially constant resistivity and thickness on said first layer; with said second layer having a resistivity greater than that of said first layer, and with said second layer having a thickness greater than that of said first layer.
Claim 22
Dependent Claim
36 words
An imaging chamber as defined in claim 20 wherein said first layer is in the order of 0.010 to 0.020 inches thick and said second layer is in the order of 0.040 to 0.060 inches thick.
Claim 23
Dependent Claim
38 words
An imaging chamber as defined in claim 20 wherein said first layer has a resistivity of about 107 to 108 ohms per square and said second layer has a resistivity of about 108 to 109 ohms per square.
Claim 24
Dependent Claim
41 words
An imaging chamber as defined in claim 20 wherein said second layer has a resistivity about at least 10 times that of said first layer and said second layer has a thickness about at least twice that of said first layer.
Claim 25
Dependent Claim
145 words
In an imaging chamber for an x-ray system, the combination of: first and secoNd substantially planar electrodes; means for mounting said electrodes in the chamber in spaced relation defining a gap therebetween; each of said electrodes having an electrical insulating substrate with a low conductivity surface at said gap and a plurality of spaced conductors along said surface; means for connecting a first voltage source to said first electrode conductors providing defined voltages therebetween; means for connecting a second voltage source to said second electrode conductors providing defined voltages therebetween; and means for connecting a third voltage source between corresponding conductors of said first and second electrodes for maintaining along said surfaces of said electrodes, electrostatic potentials substantially corresponding to the electrostatic potentials for concentric spherical metal electrodes so that the extensions of the electric field lines in said gap converge substantially to a point.
Claim 26
Dependent Claim
145 words
In an imaging chamber for an x-ray system, the combination of: first and secoNd substantially planar electrodes; means for mounting said electrodes in the chamber in spaced relation defining a gap therebetween; each of said electrodes having an electrical insulating substrate with a low conductivity surface at said gap and a plurality of spaced conductors along said surface; means for connecting a first voltage source to said first electrode conductors providing defined voltages therebetween; means for connecting a second voltage source to said second electrode conductors providing defined voltages therebetween; and means for connecting a third voltage source between corresponding conductors of said first and second electrodes for maintaining along said surfaces of said electrodes, electrostatic potentials substantially corresponding to the electrostatic potentials for concentric spherical metal electrodes so that the extensions of the electric field lines in said gap converge substantially to a point.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-24 | 1979-05-26 | 1979-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-24 | 1983-05-26 | 1983-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-24 | 1987-05-26 | 1987-11-25 | $7700.00 | Window Closed / Lapsed |