EP0315435A2
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Improvements in or relating to a streaking or framing image tube
Assignee: DRS Hadland Ltd
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Filing: 1988-11-02
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Granted: —
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Expires: 2008-11-02
Abstract
Abstract A streaking or framing image tube includes a photocathode(4), three grid electrodes (1, 2 and 3), a focus electrode (5) and an anode (6) disposed successively along the image tube. The tube is gated by applying a positive voltage pulse first to the second grid electrode (2) and then to the photocathode(4), the delay time between the application of the pulse to the second grid and the photocathode being the gated "on" time of the image tube, while during the application of the pulse to the second grid electrode (2) and the photocathode (4), the potentials of the first and third grid electrodes (1, 3) are held constant at a constant value, and accordingly ultra high speed gating (eg. allowing the passage of electrons for less than 10⁻⁹ seconds) can be achieved without effect on the magnification or resolution performance of the image tube.
Inventors
- 👤 Brian Ronald Charles C/O Imco Garfield
- 👤 Mark John C/O Imco Riches
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 16:50
CPC Classifications
H; H01; H01J; H01J31/00; H01J31/08; H01J31/50; H01J31/501; H01J31/502
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
97 words
A method of gating a streaking or framing image tube which includes a photocathode (4), an electrode assembly for forming a focussed image on the screen (12) and first, second and third grid electrodes (1, 2, 3) disposed successively along the image tube between the photocathode (4) and the said electrode assembly, said method, comprising: raising the potential of the second grid electrode (2) to allow the passage of electrons beyond the second grid electrode (2) followed by raising the potential of the photocathode (4) to stop the passage of electrons to the second grid electrode (2).
Claim 2
Independent Claim
97 words
A method of gating a streaking or framing image tube which includes a photocathode (4), an electrode assembly for forming a focussed image on the screen (12) and first, second and third grid electrodes (1, 2, 3) disposed successively along the image tube between the photocathode (4) and the said electrode assembly, said method, comprising: raising the potential of the second grid electrode (2) to allow the passage of electrons beyond the second grid electrode (2) followed by raising the potential of the photocathode (4) to stop the passage of electrons to the second grid electrode (2).
Claim 3
Dependent Claim
65 words
A method as claimed in claim 1, wherein said raising of the potentials on the photocathode (4) and second grid electrode (2) is achieved or facilitated by the application of a train of positive voltage pulses to the second grid electrode (2) and then to the photocathode (4) by means of a delay circuit connected between the second grid electrode (2) and the photocathode (4).
Claim 4
Dependent Claim
56 words
A method as claimed in claim 1 or 2, wherein the first and third grid electrodes (1, 3) are maintained at constant potentials such that variations in the potentials of the photocathode (4) and the second grid electrode (2) during the gating sequence does not disturb the focussing electric field conditions produced by the electrode assembly.
Claim 5
Dependent Claim
33 words
A method as claimed in claim 1, 2 or 3, wherein the first, second and third grid electrodes (1, 2, 3) are spaced approximately 0.5, 1.0 and 3.0mm respectively from the photocathode (4).
Claim 6
Independent Claim
33 words
A method as claimed in any preceding claim, wherein the first, second and third grid electrodes (1, 2, 3) are substantially 1000 mesh per inch with an optical transmission of greater than 70%.
Claim 7
Independent Claim
60 words
A method as claimed in any preceding claim wherein during the gated on mode the first and second electrodes (1, 2) are operated at potentials corresponding to equipotential values as determined by the electric field between the photocathode (4) and the third grid electrode (3) in the effective or notional absence of the first and second grid electrodes (1, 2).
Claim 8
Dependent Claim
46 words
A streaking or framing image tube comprising a photocathode (4), an electrode assembly for forming a focussed image on the screen (12) and first, second and third grid electrodes (1, 2, 3) disposed successively along the image tube between the photocathode and the said electrode assembly.
Claim 9
Dependent Claim
46 words
A streaking or framing image tube comprising a photocathode (4), an electrode assembly for forming a focussed image on the screen (12) and first, second and third grid electrodes (1, 2, 3) disposed successively along the image tube between the photocathode and the said electrode assembly.
Claim 10
Dependent Claim
34 words
A streaking or framing image tube as claimed in claim 7 wherein the first, second and third grid electrodes (1, 2, 3) are spaced approximately 0.5, 1.0 and 3.0mm respectively from the photocathode (4).
Claim 11
Dependent Claim
38 words
A streaking or framing image tube as claimed in claim 7 or 8 wherein the first, second and third grid electrodes (1, 2, 3) are substantially 1000 mesh per inch with an optical transmission of greater than 70%.
Claim 12
Dependent Claim
67 words
The combination of a streaking or framing image tube as claimed in claim 7, 8 or 9, with means adapted to operate in use by raising the potential of the second grid electrode (2) to allow the passage of electrons beyond the second grid electrode (2) and then raising the potential of the photocathode (4) to stop the passage of electrons to the second grid electrode (2).
Claim 13
Dependent Claim
54 words
The combination as claimed in claim 10, wherein said means comprises a delay circuit connected between the second grid electrode (2) and the photocathode (4). and means to cause the application of a train of positive voltage pulses to the second grid electrode (2) and then via the delay circuit to the photocathode (4).
Claim 14
Dependent Claim
60 words
The combination as claimed in claim 10 or 11 wherein said means is adapted to maintain the first and third grid electrodes (1, 3) at constant potentials such that variations in the potentials of the photocathode (4) and the second grid electrode (2) during the gating sequence does not disturb the focussing electric field conditions produced by the electrode assembly.
Claim 15
Dependent Claim
71 words
The combination as claimed in claim 10, 11 or 12 wherein said means is adapted to operate so that, during the gated on mode, the first and second electrodes (1, 2) are operated at potentials corresponding to the equipotential values as determined by the electric field between the photocathode (4) and the third grid electrode (3) in the effective or notional absence of the first and second grid electrodes (1, 2).
References Cited (Backward Citations)
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