US2109245A - Vacuum tube - Google Patents

Vacuum tube Download PDF

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Publication number
US2109245A
US2109245A US407652A US40765229A US2109245A US 2109245 A US2109245 A US 2109245A US 407652 A US407652 A US 407652A US 40765229 A US40765229 A US 40765229A US 2109245 A US2109245 A US 2109245A
Authority
US
United States
Prior art keywords
cathode
anode
ray
screen
electrode
Prior art date
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
US407652A
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English (en)
Inventor
Vladimir K Zworykin
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.)
Westinghouse Electric Corp
Original Assignee
Westinghouse Electric Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to BE374539D priority Critical patent/BE374539A/xx
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US407652A priority patent/US2109245A/en
Priority to DE1930623082D priority patent/DE623082C/de
Priority to FR705523D priority patent/FR705523A/fr
Application granted granted Critical
Publication of US2109245A publication Critical patent/US2109245A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/80—Arrangements for controlling the ray or beam after passing the main deflection system, e.g. for post-acceleration or post-concentration, for colour switching
    • 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
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/48—Electron guns
    • H01J29/488—Schematic arrangements of the electrodes for beam forming; Place and form of the elecrodes
    • 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
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/52—Arrangements for controlling intensity of ray or beam, e.g. for modulation

Definitions

  • Cathode-ray tubes have been utilized for many years for the measurement or the indication of electrical power, the wave-form of alternating currents or potentials, or similar conditions in electric circuits. They have also been proposed. for use in television systems, as indicated by the patent to Rosing 1,161,734. By reason of the fact, however, that it was substantially impossible to focus the cathode-ray to a well defined spot on the fluorescent screen, while still maintaining proper control of the intensity of the ray, such tubes have not, heretofore, been satisfactory as view-receiving devices.
  • Another object of my invention is to provide a cathode-ray tube capable of operating under accelerating potentials of the order of thousands of volts.
  • Another object of my invention is to provide a cathode-ray tube of the high-vacuum type so constructed as to not require continuous pumping while in use.
  • Another object of my invention is to provide a cathode-ray tube in which the electrodes are simple in'construction and. have small tot'al volume, whereby their degasiflcation, by well known processes, during evacuation of the device, is facilitated.
  • Another object of my invention is to provide a cathode-ray tube wherein the focusing of the ray is totally unaifected by .the control-potentials.
  • Another object. of my invention is to provide a cathode-ray tube wherein the ray may be focused to a well defined spot.
  • Another. object of my invention is to provide a cathode-ray tube wherein the ray is equally well defined at all points to which it is deflected upon the fluorescent screen.
  • Another object of my invention is to provide a cathode-raytube wherein the accelerating potentials may be made so large in respect to the intensity-control potentials that the deflection of the ray is not influenced by the said control potentials and is the same for all intensities.
  • a further object of my invention is to provide a cathode-ray tube wherein the, electrons are accelerated in two stages, one'stage' at a'low potential and another stageat a high potential, and wherein deflection of the "electronsis accomplishedbetween the saidstagesg j, I
  • Still another objectof my'inve'ntion is to provide a cathode-ray-tube having such characteristics as will render it especially useful in viewtransmis'sion systems.
  • acathode-ray tube comprising a preferred embodiment of my invention, includes an electron gun constituted by a thermionic cathode, a control-electrode and a primary anode, and it also includes a conductive coating, 9. per
  • I apply a very high potential between theprimary and secondary anodes, and the converging electrostatic field, set up thereby, causes the cathode-ray to be focused to a well defined spot upon the fluorescent screen.
  • the cathode is surrounded by a cup-shape shield IS.
  • the shield is carried by one oi the lead-in elements 4 thatsupport the cathode and,
  • the edge of the shield is closely adjacent to the bottom of the cup-shape control-electrode i6 and, by preventing scattering of the electrons, increases the emciency of the said electrode.
  • One of the supports 8 of the anode I 0 is provided with an extension 20 having a cupped end portion 2i adapted to carry a small amount of getter material, such as magnesium, which is flashed during the evacuation process.
  • getter material such as magnesium
  • the cathode although illustrated as being a filament, may be of the equipotential type, if desired, or of any other type capable of giving sufilcient electron emission.
  • a metallic deposit 22 covers the entire inner surface of the wall of the pear-shape portion 2 of the container and constitutes an accelerating, or focusing, anode.
  • the deposit on the extreme rounded end of the tube is sufficiently thin to be translucent and over it is applied a coating 23 of fluorescent material, such as finely divided willev ing conductive material, instead of being deposited upon a conductive surface, it is highly important that the said material be connected to the accelerating-anode 22.
  • the connection between the screen and the accelerating anode is for the purpose of carrying away the charge conveyed to it by the cathode-ray, since an. accumulated charge prevents focusing of the ray to a well defined spot.
  • a plurality of ray-deflecting devices 24 and 25 are disposed exteriorly of the vessel, intermediate the primary anode and the inner edge of the metallic deposit 22, whereby the cathode-ray may be caused to move over the fluorescent screen in any path desired.
  • the first anode I0 is maintained at a positive potential of approximately -300 volts with respect to the cathode, and the metallic coating 22, on the inner wall of the tube, which constitutes the accelerating anode, is maintained at a positive potential of approximately 3,000 volts with respect thereto.
  • the relation between the anode voltage and the voltage applied to the metallic coating is critical and I have found that, for best results, with a tube wherein the distance between the cathode and the screen 23 is approximately 20 inches, and the distance betweenthe extreme end of the anode l0 and the edge of the metallic deposit nearest thereto is about two inches, the potential of the coating should be approximately 10 times that of the anode.
  • the relatively low potential required for control of the intensity of the electron stream is an important feature of my invention. It follows from the relative positioning of the cathode, the control-electrode and the anode, the dimensions of the coaxial openings therein, and the complete enclosure of the cathode by the said control-electrode, that the number of electrons, rather than their velocity, is controlled. Since the controlpotential need be only a very small fraction of the accelerating potential between the anode and the coating 22, the electron stream is not appreciably retarded thereby, and the deflection of the stream, by the devices 24 and 25, is independent of its intensity.
  • control-electrode therefore, may be utilized to impress view-frequencies upon the device
  • a cooling medium to the exterior of the screen.
  • a transparent waterjacket may be utilized or a small fan may be mounted adjacent to the device.
  • the fluorescent spot In a view-receiving device, it is necessary that the fluorescent spot shall be well defined and shall have a definite diameter in order to cover properly. the distance between two adjacent scanning lines on the screen.
  • a conductive fluorescent screen connected to the accelerating anode is an important feature of my improved cathode-ray tube, since the screen is thereby prevented from acquiring a high negative charge that would tend to repel the cathode ray and cause blurring.
  • a cathode-ray tube including an electronsource and a first anode, a fluorescent screen and means, including said screen and a second anode adapted to be maintained at a higher voltage relative to said source than said first anode for establishing a convergent electric field around the major portion of the path traversed by an electron between said source and said screen, whereby electrons from said source may be focused to a well defined spot on said screen.
  • a cathode-ray tube comprisingan electronsource, a shield for said electron source, a control-electrode substantially enclosing said source and having a small opening in a wall thereof, a first anode having a small opening spaced from the opening in the control-electrode and in axial alignment therewith, and a second anode which is also a focusing device capable of being maintained at a high positive potential with respect to said cathode, whereby control may be had of an electron stream in said tube-without appre- 3.
  • a cathode-ray tube comprising a container exhausted to a high vacuum, an electron-source, a shield for said electron source, a control-electrode, a first accelerating electrode and a second accelerating electrode within said container, the last named electrode being constituted by a conductive deposit upon the inner surface of the said container.
  • Electron apparatus comprising an evacuated envelope, a viewing screen at one end of the envelope, means disposed at the other end of said envelope for developing a ray of electrons and directing the same toward said screen, said means comprising a cathode, a shield for said cathode, and an anode and a control electrode interposed therebetween, said electrode being in the form of an apertured shield efiective to prevent travel of electrons from said cathode to said anode along paths around said electrode, and single anode means disposed between said screen and said first-named anode and electrically disconnected and insulated from the latter to hold a potential greater than that on said first-named anode by thousands of volts, said anode means being con-- structed and disposed to develop an electrostatic field effective to focus said ray on said screen.
  • An electron tube having a coating of electrically conductive material on the interior surface of the side wall thereof, said tube provided on an end wall thereof with an interior coating characterized by the fact that the same is fluorescent and electrically conductive and translucent, the adjacent edge portions of said coatings overlap ping, and means for scanning the fluorescent coating.
  • a cathode ray tube including an electron source, a shield for said electron source, a first anode, a control electrode positioned in register and between said electron source and first anode,
  • a fluorescent screen and means including said screen and a second electrode adapted to be maintained at a higher voltage relative to said source than said first anode for establishing a convergent electric field around the major por tion of the path traversed by an electron between said source and said screen, whereby electrons from said source may be focused to a well defined spot on said screen substantially independent of the potential of said control electrode.

Landscapes

  • Electrodes For Cathode-Ray Tubes (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
US407652A 1929-11-16 1929-11-16 Vacuum tube Expired - Lifetime US2109245A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE374539D BE374539A (enrdf_load_stackoverflow) 1929-11-16
US407652A US2109245A (en) 1929-11-16 1929-11-16 Vacuum tube
DE1930623082D DE623082C (de) 1929-11-16 1930-11-05 Kathodenstrahlroehre mit Kathode, Steuerelektrode, Anode und fluoreszierendem Leuchtschirm
FR705523D FR705523A (fr) 1929-11-16 1930-11-10 Perfectionnements aux tubes à vide

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US407652A US2109245A (en) 1929-11-16 1929-11-16 Vacuum tube

Publications (1)

Publication Number Publication Date
US2109245A true US2109245A (en) 1938-02-22

Family

ID=23612963

Family Applications (1)

Application Number Title Priority Date Filing Date
US407652A Expired - Lifetime US2109245A (en) 1929-11-16 1929-11-16 Vacuum tube

Country Status (4)

Country Link
US (1) US2109245A (enrdf_load_stackoverflow)
BE (1) BE374539A (enrdf_load_stackoverflow)
DE (1) DE623082C (enrdf_load_stackoverflow)
FR (1) FR705523A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2540621A (en) * 1948-02-19 1951-02-06 Rca Corp Electron gun structure
US2712975A (en) * 1949-07-18 1955-07-12 Meditron Company Electronic diagnostic instruments
US3383536A (en) * 1964-09-22 1968-05-14 Westinghouse Electric Corp Cathode ray tube generating circular beam by lineal filament critically spaced from circular aperture

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB403973A (en) * 1932-07-04 1934-01-04 Marconi Wireless Telegraph Co Improvements in or relating to electronic amplifier valves
DE878510C (de) * 1932-07-16 1953-06-05 Aeg Elektronenstrahlroehre fuer Tonfilm- und Fernsehzwecke

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2540621A (en) * 1948-02-19 1951-02-06 Rca Corp Electron gun structure
US2712975A (en) * 1949-07-18 1955-07-12 Meditron Company Electronic diagnostic instruments
US3383536A (en) * 1964-09-22 1968-05-14 Westinghouse Electric Corp Cathode ray tube generating circular beam by lineal filament critically spaced from circular aperture

Also Published As

Publication number Publication date
BE374539A (enrdf_load_stackoverflow)
FR705523A (fr) 1931-06-09
DE623082C (de) 1935-12-12

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