US2509763A - Electric discharge tube with directional electron beam - Google Patents

Electric discharge tube with directional electron beam Download PDF

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Publication number
US2509763A
US2509763A US15141A US1514148A US2509763A US 2509763 A US2509763 A US 2509763A US 15141 A US15141 A US 15141A US 1514148 A US1514148 A US 1514148A US 2509763 A US2509763 A US 2509763A
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US
United States
Prior art keywords
field electrode
wall
tube
electrons
cup shaped
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US15141A
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English (en)
Inventor
Gier Johannes De
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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Filing date
Publication date
Application filed by Hartford National Bank and Trust Co filed Critical Hartford National Bank and Trust Co
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Publication of US2509763A publication Critical patent/US2509763A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/06—Screens for shielding; Masks interposed in the electron stream

Definitions

  • the invention relates to electric discharge tubes comprising an electrode system for producing a directional electron beam and in particular to tubes for reproduction of television images.
  • Electric charges produced on the wall of insulating material of a discharge tube comprising electrodes between which a great voltage difference at least 20,000 volts, is maintained during operation of the tube, lead to uneven voltage distributions along the wall, which are liable to provoke jump-over spark discharges and breakdowns of the wall. If these phenomena appear, the serviceability of the tube is materially reduced.
  • the space between the electrodes has in some cases been surrounded by a metal screen.
  • This screen constitutes in certain cases part of the Wall and is connected to a point of voltage source located between the high-voltage terminals.
  • the screen is enclosed between the wall and the electrodes and is connected to the anode. Due to the charge of these screens being conducted away, there is a considerable loss of electrons which, at least in part, are supplied by the cathode of the tube, so that the latter is more heavily charged.
  • the tube diameter must be considerably larger than the diameter of the electrodes, since due to the great voltage difierence cold emission may arise at the edges of the electrodes.
  • efiorts are made to work up the electrode surface with sufiicient accuracy to prevent unevennesses thereon, while constituting it generally by a metal of high Work function.
  • the invention has for its object to obviate with greater certainty undue occurrence of emission phenomena at electrodes so as to enable the tube diameter to be reduced. It is particularly useful for electron-ray tubes with directional electron beam, a magnet coil being arranged to surround the tube so as to concentrate the electron rays to form a beam of small sectional area, as is desired in the case of television tubes. In addition, magnet coils for producing deflecting fields may be arranged outside the tube. The smaller the tube diameter, the smaller is the energy required for the production of the fields by the magnet coils and the smaller may be the dimensions of the supply devices.
  • the invention relates toelectric discharge tubes with a directional electron beam in which the space intermediate two field electrodes insulated from one another for high voltage is surrounded by a wall of insulating substance, from which the field electrode adjacent the cathode is spaced by a short distance (not exceeding half the distance by which the field electrodes are spaced)
  • the term field electrodes is to be understood to mean here those electrodes which circumscribe the electric field which the electrons have to traverse.
  • the wall and at least the field electrode adjacent the cathode are separated by a metal screen which is insulated from the electrodes and extends from the wall into the space intermediate the field electrodes and terminates therein and which. screen intersects electron paths which would otherwise connect the wall to the field electrode.
  • the screen is preferably designed such that its section through a plane passing through the axis of the electron beam is curved, its convex side facing the wall and exhibits a curvature which increases the greater the distance away from the wall.
  • FIG. 1 and 2 show, by way of example, forms of discharge tubes comprising an electrode system to which the invention is applied.
  • the figures show the cylindrical part of an electron-ray tube for reproduction or transmission of television images, its glass wall I surrounding an electron-emitting cathode 2 and an accelerating anode 3.
  • the cathode 2 is secured in the tube by means of an insulating ring 4, made, for example, of ceramic material, whereas the anode 3 is gripped in the tube by means of spring members 5.
  • a voltage difference of from 20 to 30,000 v. is applied between cathode and anode.
  • the insulating ring s also serves for the arrangement of a controhelectrode 5, which is supplied with a voltage which may vary between cathode potential and a negative value of some hundreds of volts.
  • The. space between the control-electrode 6 and the wall is minimized so as to limit the tube diameter.
  • Set up along the wall of the tube is a substantially uniform distribution of the anode voltage, which, while the tube is in use, is maintained between a conductive coating 1, which is applied to the wall and on which springs 5 for gripping the anode. 3 bear and the area at which the insulating ring engages the wall I. At this voltage distribution there prevails between the wall of the tube and the control-plate B at the between the field electrodes.
  • the screen 8 provided in accordance with the invention; prevents electrons emitted from the surface of the control-electrode from reaching the glass wall I. It is, however, not sufficient for the electrons to reach the screen instead of impinging on the tube wall, since any production of secondary emission at the point of impact 'on the screen arranged to be insulated would also give rise to undue potential shift.
  • the screen extends from the wall of the tube into the space between the field electrodes 3 and 6 and its shape is such that the secondary electrons cannot move directly according to the electric lines of force towards the other field electrode 3.
  • the potential of the screen 8 may be prevented from exceeding a definite value by forming the screen in the shape shown in Fig. 2, a small aperture only being left between the controlelectrode 6 and the screen 8.
  • the tube shown in Fig. 2 comprises a second screen 9 which is inserted between the tube wall I and the field electrode 3 and extends into the space This screen retains secondary electrons which are dislodged from the wall of the tube if this wall is struck by electrons of difierent origin, in which case the drainage of these secondary electrons towards the anode would nevertheless result in potential shifts.
  • An electron discharge tube comprising a tubular envelope portion of electrical insulating material, a cathode source of a beam of electrons within said portion, a first field electrode arranged in the path of the beam and spaced from said cathode source, a second field electrode interposed between and spaced from said cathode source and said first field electrode and from said tubular envelope portion, the spacing between said second field electrode and said envelope portion being smaller than one-half the spacing between said second field electrode and said first field electrode, and a metal screening member interposed between said second field electrode and said tubular portion and insulated from said field electrodes and said tubular portion, said metal screening member having electron opaque portions shielding said tubular portion from electrons from said cathode source and from said second field electrode.
  • An electron discharge tube comprising a tubular envelope portion of electrical insulating material, a cathode source of a beam of electrons within said portion, a first field electrode arranged in the path of the beam and spaced from said cathode source, a cup shaped field electrode interposed between and spaced from said cathode source and said first field electrode and from said tubular envelope portion, the spacing between said cup shaped field electrode and said envelope portion being smaller than one-half the spacing between said cup shaped field electrode and said first field electrode, and a cup shaped metal screening member interposed between said cup shaped field electrode and said tubular portion and insulated from said field electrodes and said tubular portion, said cup shaped metal screening member having electron opaque portions shielding said tubular portion from electrons from said cathode source and from said cup shaped field electrode.
  • An electron discharge tube comprising a tubular envelope portion of electrical insulating material, a cathode source of a beam of electrons within said portion, a first field electrode arranged in the path of the beam and spaced from said cathode source, a cup shaped field electrode interposed between and spaced from said cathode source and said first field electrode and from said tubular envelope portion, the spacing between said cup shaped field electrode and said envelope portion being smaller than one-half the spacing between said cup shaped field electrode and said first field electrode, an insulating disc supporting said cathode and said cup shaped field electrode and insulating each from the other, and a cup shaped metal screening member interposed between said cup shaped field electrode and said tubular portion and supported on said insulating disc and insulated from said field electrodes and said tubular portion, said cup shaped metal screening member having electron opaque portions shielding said tubular portion from electrons from said cathode source and from said second field electrode.
  • An electron discharge tube comprising a tubular envelope portion of electrical insulating material, a cathode source of a beam. of electrons within said portion, a first field electrode arranged in the path of the beam and spaced from said cathode source, a cup shaped field electrode positioned between and spaced from said cathode source and said first field electrode and from said tubular envelope portion, the spacing between said cup shaped field electrode and said envelope portion being smaller than one-half the spacing between said cup shaped field electrode and said first field electrode, an insulating disc supporting said cathode and said cup shaped field electrode and insulating each from the other, a first cup shaped metal screening member positioned between said cup shaped field electrode and said tubular portion and supported on said insulating disc and insulated from said field electrodes and said tubular portion, said first cup shaped metal screening member having electron.

Landscapes

  • Elimination Of Static Electricity (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
US15141A 1947-04-09 1948-03-16 Electric discharge tube with directional electron beam Expired - Lifetime US2509763A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL651012X 1947-04-09

Publications (1)

Publication Number Publication Date
US2509763A true US2509763A (en) 1950-05-30

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ID=19793812

Family Applications (1)

Application Number Title Priority Date Filing Date
US15141A Expired - Lifetime US2509763A (en) 1947-04-09 1948-03-16 Electric discharge tube with directional electron beam

Country Status (4)

Country Link
US (1) US2509763A (de)
DE (1) DE818983C (de)
FR (1) FR964331A (de)
GB (1) GB651012A (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2825837A (en) * 1954-03-02 1958-03-04 Hazeltine Research Inc Electrostatic focusing system
US2888605A (en) * 1955-02-23 1959-05-26 Hughes Aircraft Co Electron gun
US3144577A (en) * 1961-10-23 1964-08-11 Philco Corp Support means for cathode ray tube gun assembly
US3529195A (en) * 1968-01-02 1970-09-15 Hughes Aircraft Co Electron gun electrode mounting arrangement
EP0905741A1 (de) * 1997-09-24 1999-03-31 Samsung Display Devices Co., Ltd. Kathodenstrahlröhre

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1100184B (de) * 1956-08-27 1961-02-23 Gen Electric Baueinheit eines Elektronenstrahlerzeugungssystems
DE19534123A1 (de) * 1995-09-14 1997-03-20 Licentia Gmbh Kathodenstrahlröhre

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1927807A (en) * 1926-09-22 1933-09-19 Gen Electric Space discharge apparatus
US1979392A (en) * 1931-05-04 1934-11-06 Siemens Ag Cathode ray tube
US2079163A (en) * 1932-05-31 1937-05-04 Farnsworth Television Inc Electron gun
GB500017A (en) * 1937-05-05 1939-02-01 Lorenz C Ag Improvements in cathode ray tubes
US2174853A (en) * 1937-08-26 1939-10-03 Hygrade Sylvania Corp Electron gun structure and method of assembly thereof
US2195914A (en) * 1937-02-22 1940-04-02 Lorenz C Ag Cathode ray tube
US2303166A (en) * 1941-01-21 1942-11-24 Bell Telephone Labor Inc Electron discharge device
US2355795A (en) * 1942-08-17 1944-08-15 Bell Telephone Labor Inc Electrode system

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1927807A (en) * 1926-09-22 1933-09-19 Gen Electric Space discharge apparatus
US1979392A (en) * 1931-05-04 1934-11-06 Siemens Ag Cathode ray tube
US2079163A (en) * 1932-05-31 1937-05-04 Farnsworth Television Inc Electron gun
US2195914A (en) * 1937-02-22 1940-04-02 Lorenz C Ag Cathode ray tube
GB500017A (en) * 1937-05-05 1939-02-01 Lorenz C Ag Improvements in cathode ray tubes
US2174853A (en) * 1937-08-26 1939-10-03 Hygrade Sylvania Corp Electron gun structure and method of assembly thereof
US2303166A (en) * 1941-01-21 1942-11-24 Bell Telephone Labor Inc Electron discharge device
US2355795A (en) * 1942-08-17 1944-08-15 Bell Telephone Labor Inc Electrode system

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2825837A (en) * 1954-03-02 1958-03-04 Hazeltine Research Inc Electrostatic focusing system
US2888605A (en) * 1955-02-23 1959-05-26 Hughes Aircraft Co Electron gun
US3144577A (en) * 1961-10-23 1964-08-11 Philco Corp Support means for cathode ray tube gun assembly
US3529195A (en) * 1968-01-02 1970-09-15 Hughes Aircraft Co Electron gun electrode mounting arrangement
EP0905741A1 (de) * 1997-09-24 1999-03-31 Samsung Display Devices Co., Ltd. Kathodenstrahlröhre
US6307315B1 (en) 1997-09-24 2001-10-23 Samsung Display Devices Co., Ltd. Cathode ray tube

Also Published As

Publication number Publication date
FR964331A (de) 1950-08-10
GB651012A (en) 1951-03-07
DE818983C (de) 1951-10-29

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