Patent JPS5021029A successfully refreshed from Google Patents.
US3649861A
Expired / Lapsed
US
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Double focus x-ray tube
Assignee: Philips Nuclear Medicine Inc
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Filing: 1970-09-09
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Granted: 1972-03-14
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Expires: 1990-09-09
Abstract
Abstract Double-focus X-ray tube has cathode focused to provide two contiguous line-focus focal spots each of 1 millimeter width. One of filaments connected to permit energization of only half-length to get fine focal spot.
Inventors
- 👤 Zed J Atlee
- 👤 Viktor W Pleil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:24
CPC Classifications
H; H01; H01J; H01J35/00; H01J35/02; H01J35/14; H01J35/153; H01J35/04; H01J35/06; H01J35/064; H01J35/066; H01J2235/00; H01J2235/06; H01J2235/068
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
143 words
A double-focus X-ray tube comprising: an anode unit including a planar faced target, a cathode unit comprising a head having a pair of substantially parallel electron focusing recesses therein and a pair of elongate filaments mounted one in each of said recesses, said cup and filaments being arranged to direct the electrons emitted by said filaments when energized over their entire lengths upon said target in a pair of contiguous rectangular focal spots of equal length so as effectively to create a unitary rectangular focal spot on said target face, means for simultaneously connecting the opposite ends of said filaments to a source of electrical energy whereby each filament emits electrons over its entire length, and means for alternatively connecting only a portion of one of said filaments to a source of electrical energy wheReby electrons are emitted from only said filament portion.
Claim 2
Dependent Claim
143 words
A double-focus X-ray tube comprising: an anode unit including a planar faced target, a cathode unit comprising a head having a pair of substantially parallel electron focusing recesses therein and a pair of elongate filaments mounted one in each of said recesses, said cup and filaments being arranged to direct the electrons emitted by said filaments when energized over their entire lengths upon said target in a pair of contiguous rectangular focal spots of equal length so as effectively to create a unitary rectangular focal spot on said target face, means for simultaneously connecting the opposite ends of said filaments to a source of electrical energy whereby each filament emits electrons over its entire length, and means for alternatively connecting only a portion of one of said filaments to a source of electrical energy wheReby electrons are emitted from only said filament portion.
Claim 3
Dependent Claim
20 words
An X-ray tube as set forth in claim 1 wherein said pair of focal spots are of the same width.
Claim 4
Dependent Claim
22 words
An X-ray tube as set forth in claim 2 wherein said pair of focal spots are each of 1 millimeter in width.
Claim 5
Dependent Claim
21 words
An X-ray tube as set forth in claim 2 wherein said one filament portion is one half of said one filament.
Claim 6
Dependent Claim
38 words
An X-ray tube as set forth in claim 3 wherein said filaments are electrically insulated from said head, and means are provided for applying an electrical potential to said head different from the potential applied to said filaments.
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) | 1975-03-14 | 1975-09-13 | 1976-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-14 | 1979-09-13 | 1980-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-14 | 1983-09-13 | 1984-03-14 | $7700.00 | Window Closed / Lapsed |