Patent US3875440A successfully refreshed from Google Patents.
US3875440A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cascade image intensifier tube with independently sealed sections
Assignee: Electron Physics Ltd
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Filing: 1972-11-22
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Granted: 1975-04-01
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Expires: 1992-11-22
Abstract
Abstract A cascade image intensifier is provided with a mica sheet extending across the interior of the tube and sealed to it to separate electrically each stage. A phosphor screen of one stage is formed on one side of the mica sheet and a photocathode of the next stage is formed on the other side. The photocathode may be at a much lower potential than the phosphor screen on the other side of the sheet. This allows electrons to be accelerated in cascade without the use of very high voltages.
Inventors
- 👤 James Dwyer Mcgee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:20
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/02; H01J29/10; H01J29/36; H01J29/38; H01J29/385; H01J31/00; H01J31/08; H01J31/50; H01J31/508
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
140 words
An image intensifier tube comprising an evacuated enclosure; an input window and an output window forming parts of said enclosure, said evacuated enclosure having impervious walls extending between said input and output windows; a first photocathode formed on the input window; a first phosphor screen formed on the output window; and at least one intermediate stage formed by a transparent insulating sheet extending across the interior of the tube and forming a gas-tight seal with The walls of the tube, said sheet extending completely across the interior of the tube and projecting beyond its external walls to provide a barrier electrically isolating parts of the tube on either side of the sheet from substantial potential differentials, a second phosphor screen formed on a first side of said sheet and a second photocathode formed on a second side of said sheet.
Claim 2
Dependent Claim
140 words
An image intensifier tube comprising an evacuated enclosure; an input window and an output window forming parts of said enclosure, said evacuated enclosure having impervious walls extending between said input and output windows; a first photocathode formed on the input window; a first phosphor screen formed on the output window; and at least one intermediate stage formed by a transparent insulating sheet extending across the interior of the tube and forming a gas-tight seal with The walls of the tube, said sheet extending completely across the interior of the tube and projecting beyond its external walls to provide a barrier electrically isolating parts of the tube on either side of the sheet from substantial potential differentials, a second phosphor screen formed on a first side of said sheet and a second photocathode formed on a second side of said sheet.
Claim 3
Dependent Claim
14 words
The image intensifier tube of claim 1, in which the insulating sheet is mica.
Claim 4
Dependent Claim
30 words
The image intensifier tube of claim 1, in which the tube is of soda-lime glass and a low-melting point solder glass is provided to seal the mica to the tube.
Claim 5
Dependent Claim
161 words
An image intensifier tube comprising an evacuated enclosure; an input window and an output window forming parts of said enclosure, said evacuated enclosure having impervious walls exending between said input and output windows; a first photocathode formed on the input window; a first phosphor screen formed on the output window; and at least one intermediate stage formed by a transparent insulating sheet extending across the interior of the tube and a pair of washers, said pair of washers being sealed to the internal walls of said tube and sandwiching the periphery of said insulating sheet therebetween to form gas-tight seal with the walls of the tube, said insulating sheet providing a barrier electrically isolating parts of the tube on either side of the sheet from substantial potential differentials, a second phosphor screen formed on a first side of said sheet and a second photocathode formed on a second side of said sheet, said tube and said washers being of borosilicate glass.
Claim 6
Dependent Claim
161 words
An image intensifier tube comprising an evacuated enclosure; an input window and an output window forming parts of said enclosure, said evacuated enclosure having impervious walls exending between said input and output windows; a first photocathode formed on the input window; a first phosphor screen formed on the output window; and at least one intermediate stage formed by a transparent insulating sheet extending across the interior of the tube and a pair of washers, said pair of washers being sealed to the internal walls of said tube and sandwiching the periphery of said insulating sheet therebetween to form gas-tight seal with the walls of the tube, said insulating sheet providing a barrier electrically isolating parts of the tube on either side of the sheet from substantial potential differentials, a second phosphor screen formed on a first side of said sheet and a second photocathode formed on a second side of said sheet, said tube and said washers being of borosilicate glass.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |