US4126805A
Expired / Lapsed
US
⏱️ 0.0 years remaining
X-ray tubes
Assignee: QED Intellectual Property Ltd
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Filing: 1976-10-12
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Granted: 1978-11-21
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Expires: 1996-10-12
Abstract
Abstract An X-ray tube is described in which, in order to produce a well defined electron beam which can be accurately focussed on the target of the tube, the cathode comprises a flat plate member, such as a tape or foil, the surface finish of which is sufficiently smooth that electrons are emitted therefrom with lateral energies below 0.2 electron volts. The aforementioned surface finish is such that irregularities in the electron-emitting surface of the cathode do not exceed one micron in amplitude.
Inventors
- 👤 Robert P. Randall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:50
CPC Classifications
H; H01; H01J; H01J35/00; H01J35/02; H01J35/04; H01J35/06; H01J35/064; H01J35/066; H01J35/14; H01J35/147
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
74 words
An X-ray tube having a cathode comprising a plate member formed so that irregularities in the electron-emitting surface thereof do not exceed one micron in amplitude, means for generating an extraction field for withdrawing electrons from said member in substantially a single direction, an X-ray emissive target member, and means for focussing said electrons on a region of said target member which is of area substantially less than the area of said plate member.
Claim 2
Dependent Claim
74 words
An X-ray tube having a cathode comprising a plate member formed so that irregularities in the electron-emitting surface thereof do not exceed one micron in amplitude, means for generating an extraction field for withdrawing electrons from said member in substantially a single direction, an X-ray emissive target member, and means for focussing said electrons on a region of said target member which is of area substantially less than the area of said plate member.
Claim 3
Dependent Claim
17 words
A tube according to claim 1 wherein said plate member comprises a tape formed of rolled tantalum.
Claim 4
Dependent Claim
15 words
A tube according to claim 2 including resilient means for maintaining said tape under tension.
Claim 5
Dependent Claim
38 words
A tube according to claim 1 including a suppression structure formed with an open channel dimensioned to accommodate said plate member, the channel having lips which protrude above said plate member in a direction toward the target member.
Claim 6
Dependent Claim
42 words
A tube according to claim 1 including an apertured focussing electrode spaced from said plate member and positioned so that said electrons pass through the aperture thereof, the said focussing electrode being formed with a substantially planar surface facing said plate member.
Claim 7
Dependent Claim
21 words
A tube according to claim 5 wherein said focussing electrode is formed with a curved surface facing away from said member.
Claim 8
Dependent Claim
20 words
A tube according to claim 5 including an apertured guard member interposed between said plate member and said focussing electrode.
Claim 9
Dependent Claim
17 words
A tube according to claim 1 including means for deflecting said electrons relative to said target member.
Claim 10
Dependent Claim
13 words
A tube according to claim 8 wherein said deflecting means includes deflection coils.
Claim 11
Dependent Claim
33 words
A tube according to claim 1 wherein said electrons are constrained to travel to said target member as a beam which impinges upon a region of said target member about 1mm in width.
Claim 12
Dependent Claim
28 words
A tube according to claim 10 including a drift tube and means for constraining said beam to pass through said drift tube on its way to said target.
Claim 13
Dependent Claim
57 words
A tube according to claim 1 wherein the focussing means include means for focussing said electrons to a beam impinging on an elongated area of said target member, and including means for deflecting said beam to selectively move said elongated area relative to the target member along a direction transverse to the length of said elongated area.
Claim 14
Dependent Claim
12 words
A tube according to claim 1 wherein said plate member is flat.
References Cited (Backward Citations)
US2362816A
Cited
US3046430A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-11-20 | 1982-05-22 | 1982-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-11-20 | 1986-05-22 | 1986-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-11-20 | 1990-05-22 | 1990-11-21 | $7700.00 | Window Closed / Lapsed |