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US2555091A - Cathode-ray tube - Google Patents

Cathode-ray tube Download PDF

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Publication number
US2555091A
US2555091A US72863A US7286349A US2555091A US 2555091 A US2555091 A US 2555091A US 72863 A US72863 A US 72863A US 7286349 A US7286349 A US 7286349A US 2555091 A US2555091 A US 2555091A
Authority
US
United States
Prior art keywords
cathode
potential
ray tube
layer
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
US72863A
Other languages
English (en)
Inventor
Lubszynski Hans Gerhard
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.)
EMI Ltd
Electrical and Musical Industries Ltd
Original Assignee
EMI Ltd
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
Application filed by EMI Ltd filed Critical EMI Ltd
Application granted granted Critical
Publication of US2555091A publication Critical patent/US2555091A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/26—Image pick-up tubes having an input of visible light and electric output
    • H01J31/28—Image pick-up tubes having an input of visible light and electric output with electron ray scanning the image screen
    • H01J31/34—Image pick-up tubes having an input of visible light and electric output with electron ray scanning the image screen having regulation of screen potential at cathode potential, e.g. orthicon
    • H01J31/38—Tubes with photoconductive screen, e.g. vidicon

Definitions

  • This invention relates to circuit arrangements embodying cathode ray tubes of the type which employ a, target electrode which is scanned by an electron beam for the purpose of generating signals which are suitable" for example for use in television transmitting systems.
  • a circuit arrangement embodying a cathode ray tube having a target electrode comprising a photo-conductive layer provided on a conductive signal electrode and arranged to receive an optical image, means for scanning said layer with a low-velocity scanning beam 50 that the equilibrium potential of the scanned surface of said layer corresponds substantially to that of the cathode which generates said scanning beam and means for maintaining said signal electrode at a positive potential with respect to the potential of said cathode.
  • the cathode ray tube 1 comprises a target electrode 2 composed of a transparent insulating layer 3, such as glass or mica, on one side of which is deposited a semitransparent signal plate 4. On the top of this signal plate 4 is deposited a layer of photo-conductive material 5, such as zinc selenide.
  • a target electrode 2 composed of a transparent insulating layer 3, such as glass or mica, on one side of which is deposited a semitransparent signal plate 4.
  • a layer of photo-conductive material 5 such as zinc selenide.
  • the layer of zinc selenide is arranged to be scanned by a low-velocity scanning beam which is generated by a suitably disposed electron gun.
  • the electron gun comprises a cathode 6, a cathode shield 7, an apertured anode -8 and a further electrode 9 consisting of a metallic wall coating.
  • the cathode 5 may be maintained at earth potential, the'shield l at a negative potential thereto, the anode 8 at apositive potential and the electrode 9 usually at a slightly lower positive potential than the anode 3.
  • Near to the target electrode 2 is a decelerating electrode I0 which is maintained at a less positive potential than the electrode 9.
  • the electrodes 5IU are conventionally shown as deriving their potentials from a potentiometer l I connected across a source of potential I2.
  • the electron beam from the gun is accelerated b the anode '8 and decelerated by the electrodes 9 and It and is scanned over the surface of the target electrode 2 by scanning coils indicated at E3.
  • the electron beam is focussed by and is arranged to scan the surface of the target electrode in the presence Of a longitudinal magnetic field set up by a solenoid l4 and the arrangement is such that the beam is caused to impinge on the target electrode substantially normally throughout the whole scanning cycle in known manner.
  • the signal plate 4 is connected to a signal resistance l5 and is maintained at a slightly positive potential of the order of a few volts with respect to the cathode 6 of the electron gun, the magnitude of said positive potential determining the sensitivity of the tube.
  • An image of the object for transmission is projected through the insulating layer and through the transparent signal plate on to the layer of zinc selenide. In the absence of illumination, the surface of the layer 5 scanned by the cathode ray beam will be charged to the potential of the cathode of the electron gun and a potential difference will thus be set up through the target electrode.
  • a tube constructed as described above is suitable for use in television transmission and is also suitquires to be treated with caesium or other materials of low work function the secondary emission-ratio of the target electrode can be maintained-low and hence a better modulation of the electron beam can be obtained rendering it eminently suitable for use where the unrequired electrons are returned to a multiplier.
  • a circuit arrangement embodying a cathode ray tube having a target electrode comprising a photo-conductive layer provided on a conductive signal electrode and arranged to receive an optical image including means for scanning said layer with a, low-velocity scanning beam with the equilibrium potential of the scanned surface of said layer corresponding substantially to that of the cathode which generates said scanning beam, and means for maintaining said signal electrode at a positive potential with respect to the potential of said cathode.

Landscapes

  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Radar Systems Or Details Thereof (AREA)
US72863A 1948-02-03 1949-01-26 Cathode-ray tube Expired - Lifetime US2555091A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3072/48A GB665877A (en) 1948-02-03 1948-02-03 Improvements in or relating to circuit arrangements embodying cathode ray tubes

Publications (1)

Publication Number Publication Date
US2555091A true US2555091A (en) 1951-05-29

Family

ID=9751460

Family Applications (1)

Application Number Title Priority Date Filing Date
US72863A Expired - Lifetime US2555091A (en) 1948-02-03 1949-01-26 Cathode-ray tube

Country Status (3)

Country Link
US (1) US2555091A (fr)
FR (1) FR979860A (fr)
GB (1) GB665877A (fr)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2598401A (en) * 1948-02-18 1952-05-27 Emi Ltd Electron discharge device suitable for use as television transmitting tubes
US2699512A (en) * 1951-11-21 1955-01-11 Sheldon Edward Emanuel Camera for invisible radiation images
US2740918A (en) * 1950-12-16 1956-04-03 Emi Ltd Cathode ray tubes
US2749463A (en) * 1951-10-24 1956-06-05 Bell Telephone Labor Inc Solid state television pick-up tube
US2816954A (en) * 1952-10-23 1957-12-17 David A Huffman Infra-red television camera
US2864031A (en) * 1950-12-30 1958-12-09 Rca Corp Electrical storage tube
US2890359A (en) * 1953-06-13 1959-06-09 Philips Corp Camera tube
US2911562A (en) * 1957-09-20 1959-11-03 Thompson Ramo Wooldridge Inc Television camera circuits
US2973445A (en) * 1951-03-09 1961-02-28 Machlett Lab Inc Device for detection, conversion, and amplification of x-ray images
US3003075A (en) * 1950-12-05 1961-10-03 Rca Corp Infra-red sensitive devices
US3051860A (en) * 1957-11-27 1962-08-28 Ass Elect Ind Manchester Ltd Image scanner for electron microscopes
US3087087A (en) * 1956-02-28 1963-04-23 Gen Dynamics Corp Electron beam control apparatus for light responsive display tubes
US3321656A (en) * 1954-03-11 1967-05-23 Edward E Sheldon Television camera tube with lead oxide screen

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1747988A (en) * 1925-05-27 1930-02-18 Gen Electric Transmission of pictures and views
US2150980A (en) * 1935-02-09 1939-03-21 Emi Ltd Electron discharge device
US2324504A (en) * 1940-11-28 1943-07-20 Rca Corp Television transmitting system
US2404098A (en) * 1941-06-27 1946-07-16 Rca Corp Television transmitting system
US2404046A (en) * 1941-06-21 1946-07-16 Rca Corp Television transmitting apparatus
US2407485A (en) * 1944-06-01 1946-09-10 Farnsworth Television & Radio Television control system
US2415842A (en) * 1943-01-30 1947-02-18 Bell Telephone Labor Inc Electrooptical device
US2489127A (en) * 1947-06-14 1949-11-22 Rca Corp High capacitance target

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1747988A (en) * 1925-05-27 1930-02-18 Gen Electric Transmission of pictures and views
US2150980A (en) * 1935-02-09 1939-03-21 Emi Ltd Electron discharge device
US2324504A (en) * 1940-11-28 1943-07-20 Rca Corp Television transmitting system
US2404046A (en) * 1941-06-21 1946-07-16 Rca Corp Television transmitting apparatus
US2404098A (en) * 1941-06-27 1946-07-16 Rca Corp Television transmitting system
US2415842A (en) * 1943-01-30 1947-02-18 Bell Telephone Labor Inc Electrooptical device
US2407485A (en) * 1944-06-01 1946-09-10 Farnsworth Television & Radio Television control system
US2489127A (en) * 1947-06-14 1949-11-22 Rca Corp High capacitance target

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2598401A (en) * 1948-02-18 1952-05-27 Emi Ltd Electron discharge device suitable for use as television transmitting tubes
US3003075A (en) * 1950-12-05 1961-10-03 Rca Corp Infra-red sensitive devices
US2740918A (en) * 1950-12-16 1956-04-03 Emi Ltd Cathode ray tubes
US2864031A (en) * 1950-12-30 1958-12-09 Rca Corp Electrical storage tube
US2973445A (en) * 1951-03-09 1961-02-28 Machlett Lab Inc Device for detection, conversion, and amplification of x-ray images
US2749463A (en) * 1951-10-24 1956-06-05 Bell Telephone Labor Inc Solid state television pick-up tube
US2699512A (en) * 1951-11-21 1955-01-11 Sheldon Edward Emanuel Camera for invisible radiation images
US2816954A (en) * 1952-10-23 1957-12-17 David A Huffman Infra-red television camera
US2890359A (en) * 1953-06-13 1959-06-09 Philips Corp Camera tube
US3321656A (en) * 1954-03-11 1967-05-23 Edward E Sheldon Television camera tube with lead oxide screen
US3087087A (en) * 1956-02-28 1963-04-23 Gen Dynamics Corp Electron beam control apparatus for light responsive display tubes
US2911562A (en) * 1957-09-20 1959-11-03 Thompson Ramo Wooldridge Inc Television camera circuits
US3051860A (en) * 1957-11-27 1962-08-28 Ass Elect Ind Manchester Ltd Image scanner for electron microscopes

Also Published As

Publication number Publication date
GB665877A (en) 1952-01-30
FR979860A (fr) 1951-05-04

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