US4091311A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Modulatable, hollow beam electron gun
Assignee: Norden Systems Inc
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Filing: 1976-12-17
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Granted: 1978-05-23
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Expires: 1996-12-17
Abstract
Abstract A modulatable, hollow beam electron gun assembly includes an electron-optical (E-O) column having a fixed diameter ring, dispenser type cathode assembly for providing a hollow electron beam through thermionic emission from a hollow cylindrical cathode element, first and second control grid assemblies, a first anode assembly and a second anode assembly, which in combination with a beam modulator assembly comprises an electrostatic coaxial lens assembly. The grid and anode assemblies provide control of the emitted beam current density. The beam modulator assembly includes an axial electrode positioned along the longitudinal axis of the second anode assembly and first and second hollow, anode modulator rings disposed within the second anode and circumscribing a different portion of the axial electrode, each modulator ring responsive to modulation signals presented to each at a substantially complementary magnitude and polarity to provide a hollow electron beam having an average diameter provided by an instantaneous outer diameter and inner diameter value, the ratio of which defines an aspect ratio of the beam.
Inventors
- 👤 Charles Mendelsohn
- 👤 Holger Martin Luther
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:48
CPC Classifications
H; H01; H01J; H01J3/00; H01J3/02; H01J29/00; H01J29/02; H01J29/04; H01J29/46; H01J29/48; H01J29/488
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
372 words
A modulatable, hollow beam electron gun apparatus having an electron-optical (E-O) column for providing a hollow electron beam of instantaneous average diameter determined by instantaneous inner diameter and outer diameter values, for use in a CRT which provides a visual image in response to video signals, bias voltage signals, anode voltage signals, and a pair of concurrent beam modulation signals presented thereto from a system having a source of video signals, a source of bias signals, a source of anode voltage signals, and a source of concurrent modulation signals, comprising: cathode assembly means, disposed at one end of a longitudinal axis of the E-O column and connected for response to the video source, said cathode means having an electron emitting surface adapted for providing a hollow electron beam of determined inner and outer diameter at a current density in dependence on the video signal magnitude; control grid means, disposed along a successive portion of said longitudinal axis coaxially with, and adjacent to, the electron emitting surface of said cathode means and connected for response to the bias voltage source, said control grid means providing modulation of the electron beam current density in response to the magnitude of the bias voltage signals, in cooperative relationship with said cathode means; first anode means, coaxially disposed along another successive portion of said longitudinal axis adjacent to said control grid means and connected for response to the anode voltage source, said first anode means providing a first electrostatic field in response to the magnitude of the anode voltage signal, said first electrostatic field being relatively positive with respect to said cathode means and said control grid to provide acceleration of the hollow electron beam emitted by said cathode means; and electrostatic coaxial lens means, coaxially disposed along another successive portion of said longitudinal axis adjacent to said first anode means and connected for response to the anode voltage source and to the source of concurrent modulation signals, said coaxial lens means providing further acceleration of the electron beam in response to the magnitude of the anode voltage signal, and said coaxial lens means providing a change in the instantaneous average diameter of the emitted electron beam in dependence on the magnitudes of the concurrent modulation signals.
Claim 2
Dependent Claim
372 words
A modulatable, hollow beam electron gun apparatus having an electron-optical (E-O) column for providing a hollow electron beam of instantaneous average diameter determined by instantaneous inner diameter and outer diameter values, for use in a CRT which provides a visual image in response to video signals, bias voltage signals, anode voltage signals, and a pair of concurrent beam modulation signals presented thereto from a system having a source of video signals, a source of bias signals, a source of anode voltage signals, and a source of concurrent modulation signals, comprising: cathode assembly means, disposed at one end of a longitudinal axis of the E-O column and connected for response to the video source, said cathode means having an electron emitting surface adapted for providing a hollow electron beam of determined inner and outer diameter at a current density in dependence on the video signal magnitude; control grid means, disposed along a successive portion of said longitudinal axis coaxially with, and adjacent to, the electron emitting surface of said cathode means and connected for response to the bias voltage source, said control grid means providing modulation of the electron beam current density in response to the magnitude of the bias voltage signals, in cooperative relationship with said cathode means; first anode means, coaxially disposed along another successive portion of said longitudinal axis adjacent to said control grid means and connected for response to the anode voltage source, said first anode means providing a first electrostatic field in response to the magnitude of the anode voltage signal, said first electrostatic field being relatively positive with respect to said cathode means and said control grid to provide acceleration of the hollow electron beam emitted by said cathode means; and electrostatic coaxial lens means, coaxially disposed along another successive portion of said longitudinal axis adjacent to said first anode means and connected for response to the anode voltage source and to the source of concurrent modulation signals, said coaxial lens means providing further acceleration of the electron beam in response to the magnitude of the anode voltage signal, and said coaxial lens means providing a change in the instantaneous average diameter of the emitted electron beam in dependence on the magnitudes of the concurrent modulation signals.
Claim 3
Dependent Claim
58 words
The electron gun apparatus of claim 1, wherein said cathode assembly means is a fixed diameter ring, dispenser type cathode having a hollow, cylindrical electron emitting surface of determined inner and outer diameter for providing said hollow electron beam of substantially equal determined inner and outer diameter, said cathode assembly including an outer casing structure of determined diameter.
Claim 4
Dependent Claim
18 words
The electron gun apparatus of claim 2, wherein said control grid means comprises first and second grid means.
Claim 5
Dependent Claim
164 words
The electron gun apparatus of claim 3 wherein each of said first and second grid means comprise a hollow cylindrical structure having coaxial input and output apertures, said first grid means having an input aperture of determined diameter greater than that of said cathode means casing structure and having an output aperture of determined diameter greater than the outer diameter of said cylindrical electron emitting surface, said first grid means enclosing said cathode means without interference with the emitted hollow beam, said second grid means coaxially disposed with said first grid means and having an input aperture of determined diameter equal to that of said first grid means input aperture and having an output aperture of determined diameter for providing a restriction on the maximum divergence of the emitted electron beam, each of said grid means being connected for response to the source of the bias voltage signals for providing modulation of the electron beam current density in cooperative relationship with said cathode means.
Claim 6
Dependent Claim
339 words
The electron gun apparatus of claim 1, wherein said electrostatic coaxial lens assembly means comprises: second anode means, having a hollow cylindrical structure of determined longitudinal length with coaxial input and output apertures, said second anode means connected for response to the anode voltage source for providing a second electrostatic field in response to the magnitude of the anode voltage signal, said second electrostatic field being relatively positive with respect to said cathode means and said control grid means, said second electrostatic field in combination with said first electrostatic field providing an increased beam acceleration, and low beam divergence angle at the emitting surface of said cathode means; electrostatic beam modulator assembly means, nested within said second anode means in an axially symmetrical manner, and including axial electrode means having a determined longitudinal length equal to that of said second anode means and suspended on the central longitudinal axis of said second anode means through electrically conductive support means connected to the structure of said second anode means, said axial electrode means providing a positive axial electrostatic field in response to the anode voltage signal presented through said support means, said beam modulator means further including first and second anode ring modulator means relatively disposed at a determined drift distance along a different portion of the axial electrode means, each having a hollow cylindrical structure of determined longitudinal length with coaxial input and output apertures, the combined longitudinal lengths of each anode ring and the drift distance being smaller than the longitudinal length of said second anode means, each of said ring modulator means providing a spatial enclosure along the respectively disposed portion of the axial electrode means within the second anode means, each of said modulator ring means being electrically isolated from the structure of said second anode means through a corresponding one of a pair of isolation resistance means and each ring being responsive to a different one of a pair of concurrent modulation signals presented thereto through a corresponding one of a pair of electrical conductors.
Claim 7
Dependent Claim
85 words
The electron gun apparatus of claim 5 further including lens centering means, coaxially disposed along another successive portion of said longitudinal axis adjacent to said electrostatic coaxial lens means, said lens centering means including a pair of electrodes disposed in each of two orthogonal planes, each pair connected for response to a different output of the bias voltage source for providing centering of said emitted hollow electron beam along the central longitudinal axis of the E-O column in response to bias voltage signals presented thereto.
Claim 8
Dependent Claim
122 words
The electron gun apparatus of claim 5, wherein each of said ring modulator means provides an electrostatic field within the respective spatial enclosure provided thereby at a steady state magnitude in dependence on the magnitude of the anode voltage signal, each of said ring modulator means further providing a complementary modulated change in the magnitude of the respective electrostatic field in response to the absolute magnitude of a respective one of the concurrent pairs of modulation signals presented thereto, the modulated change in the electrostatic fields provided by said first and second ring modulator means, in combination, causing a corresponding divergence and recollimation of the electron beam propagating through the beam modulator means to provide said change in the instantaneous beam diameter.
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) | 1981-05-22 | 1981-11-21 | 1982-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-22 | 1985-11-21 | 1986-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-22 | 1989-11-21 | 1990-05-23 | $7700.00 | Window Closed / Lapsed |