US2497660A - Leakage minimizing shield for electron discharge devices - Google Patents

Leakage minimizing shield for electron discharge devices Download PDF

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Publication number
US2497660A
US2497660A US600009A US60000945A US2497660A US 2497660 A US2497660 A US 2497660A US 600009 A US600009 A US 600009A US 60000945 A US60000945 A US 60000945A US 2497660 A US2497660 A US 2497660A
Authority
US
United States
Prior art keywords
leakage
envelope
screen
electron discharge
cathode ray
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
US600009A
Other languages
English (en)
Inventor
George F Devine
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.)
General Electric Co
Original Assignee
General Electric Co
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 BE476954D priority Critical patent/BE476954A/xx
Application filed by General Electric Co filed Critical General Electric Co
Priority to US600009A priority patent/US2497660A/en
Priority to GB24396/46A priority patent/GB638139A/en
Application granted granted Critical
Publication of US2497660A publication Critical patent/US2497660A/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
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/86—Vessels; Containers; Vacuum locks
    • H01J29/867—Means associated with the outside of the vessel for shielding, e.g. magnetic shields
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/64—Constructional details of receivers, e.g. cabinets or dust covers
    • H04N5/65—Holding-devices for protective discs or for picture masks

Definitions

  • This invention relates to electron discharge devices such as cathode ray tubes and particularly to apparatus for minimizing the leakage of current from such devices to the supporting structures thereof.
  • Cathode ray tubes commonly comprise an envelope within which is arranged an electron gun for producing a beam of electrons, together with an accelerating electrode and afluorescent screen on which the beam is caused to impinge and produce a luminous spot the intensity of which may be varied in accordance with a signal introduced on a control grid in the path of the beam.
  • the supporting structure for a cathode ray tube frequently comprises a frame or collar arranged about the envelope of the tube peripherally of the luminescent screen, and there is a tendency for current to leak through the envelope to the supporting structure.
  • the leakage is negligible in dry weather but during conditions of high humidity in the atmosphere the rate of leakage may become appreciable and as a result the signal portrayed on the luminescent screen is affected thereby.
  • the length of a horizontal trace on a cathode ray screen will change with the intensity of the signal so that if a cathode ray tube is provided to give a calibrated reading this reading will be in error when the atmospheric conditions change. Accordingly it is an object of this invention to provide an electron discharge device including an improved arrangement for minimizing the leakage of current from a high potential area of the interior surface of the envelope to the exterior.
  • Fig. l is a side elevation, partly in section, of a portion of a cathode ray tube embodying the invention
  • Fig. 2 is a perspective view, partly broken away, of the external high voltage element shown in Fig. 1
  • Fig. 3 is a diagrammatic view of the cathode ray tube of Fig. 1 and its asso-
  • the cathode ray tube illustrated in Fig. 1 comprises a glass envelope I including a neck por-' tion 2, only a part of which is shown, and a bowl 3.
  • the beam forming electrodes or electron gun (not shown) is arranged in the usual manner in the neck portion 2, and the face of the tube is provided with a fluorescent screen 4 which becomes luminescent when the electron beam' impinges thereon.
  • An accelerating electrode or anode 5 is provided on the inner walls of the bowl; this electrode may be a coating on the walls or a separate sheet metal electrode.
  • a conducting terminal for the electrode 5 is secured on the outside of the tube as indicated at 6.
  • a resilient collar 1 of rubber or other suitable material is placed about the tube at its greatest diameter around the periphery of the screen, and a viewing plate 8 is secured over The tube is connected in a suitable circuit as indicated in Fig. 3.
  • a suitable high voltage source In shunted by a resistor or potentiometer H is connected to the electrodes as illustrated.
  • a control grid shown at I4 is connected to a source of signals It to vary the intensity of the electron beam in accordance with the signal.
  • the anode 5 is connected through the cap 6 to the high potential positive end of the potentiomi eter.
  • a high positive potential with respect to the cathode exists on the fluorescent screen 4 due to secondary emission.
  • This potential may be of the same order of magnitude as the potential of the accelerating anode 5.
  • the presence of leakage may be detected by changing the intensity of the electron beam; when leakage is present the length of the trace produced-by the sweep of the beam changes when the intensity is changed.
  • deflecting members are provided about the neck 2 of the tube to deflect the beam inthe.
  • a conducting band' i's provided about the outer wall of the en-- velopead-jacent theperiphery of the luminescent.
  • an electron discharge device including an envelope, a luminescent surface positioned on an inner wall of said envelope, a cathode positioned within said envelope, accelerating electrode means located within said envelope between said cathode and said surface, means for impressing on said electrode a potential sufiicient to direct electrons emitted by said cathode onto said surface whereby during operation of said device said surface acquires a high positive potential due to secondary emission and tends to 'produce leakage through said envelope, and -nie'ans -forminimizing leakage through said envelope comprising a conductive band arranged 4 about the outside of; said envelope adjacent the screen. As shown in Figs. 1. and 2, this band'm'ay 4 tential' is of the same order of magnitude as the positive potential on the fluorescent screen 4.
  • the cathode ray tube may be in a relatively exposed position'so that there may be some chance of the operator's touchlmgthe high" potential ring.
  • it is desirable to provide a resistance of' several megohms between the ring and the anode, terminal 6 as illustrated at l9 in Fig. 4. This re "stance” limits the current which can be drawn. through the ring l6 should the operator come incontact therewith. s
  • the wire ring It may be embedded in the collar i as illustrated in Fig. 5 where it acts as a rein-forcing member for the collar as well as a high potentialband. for minimizing leakage. Locationof the ring l8 in the collar in this manner avoids-the necessity of replacing the ring each time a new tube-is introduced.
  • an electron. discharge device including, an. envelope, means including a cathode and a. first anode for developing an electron beam, 9.
  • an electron discharge de- I vice of the cathode ray type having a luminescent screen on an inner wall surface thereof and which attains a high" positive potential during operation of the device due to secondary emission, a conducting member arranged about the 1 outside. of said device adjacent said screen, and means including a high resistance element for.
  • an electron discharge device of the cathode ray type having an envelope provided with a luminescent screen'on an inner wall thereof, a supporting means for said device comprising a collar of flexible material arranged about said envelope adjacent the periphery of said screen, a conducting. member embedded in said collar, and means for impr ssing onsaid membera high; positive. potential of the same -;R'+;-'orlderofi magnitude-as. the potentialof said screen.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
  • Measurement Of Radiation (AREA)
US600009A 1945-06-18 1945-06-18 Leakage minimizing shield for electron discharge devices Expired - Lifetime US2497660A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BE476954D BE476954A (en)van) 1945-06-18
US600009A US2497660A (en) 1945-06-18 1945-06-18 Leakage minimizing shield for electron discharge devices
GB24396/46A GB638139A (en) 1945-06-18 1947-08-16 Improvements in and relating to electron discharge devices

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US600009A US2497660A (en) 1945-06-18 1945-06-18 Leakage minimizing shield for electron discharge devices

Publications (1)

Publication Number Publication Date
US2497660A true US2497660A (en) 1950-02-14

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ID=24402005

Family Applications (1)

Application Number Title Priority Date Filing Date
US600009A Expired - Lifetime US2497660A (en) 1945-06-18 1945-06-18 Leakage minimizing shield for electron discharge devices

Country Status (3)

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US (1) US2497660A (en)van)
BE (1) BE476954A (en)van)
GB (1) GB638139A (en)van)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2545524A (en) * 1945-08-29 1951-03-20 Rca Corp Schmidt television projection system
US2551790A (en) * 1949-04-01 1951-05-08 Rca Corp Positioning structure for cathode-ray tubes
US2559353A (en) * 1950-07-25 1951-07-03 Richard A Fisch Mounting and protecting device for cathode-ray tubes
US2602114A (en) * 1950-04-10 1952-07-01 Richard A Fisch Insulating ring and protective device for cathode-ray tubes
US2642550A (en) * 1950-01-19 1953-06-16 Nat Res Dev Electronic information storage device
US2663011A (en) * 1949-07-06 1953-12-15 Sylvania Electric Prod Cathode-ray tube support
US2684477A (en) * 1951-05-21 1954-07-20 Richard A Fisch Mounting and insulating ring for cathode-ray and television tubes
US2756415A (en) * 1949-06-01 1956-07-24 Rca Corp Schmidt television projector arrangement
US2898586A (en) * 1956-06-25 1959-08-04 Sylvania Electric Prod Television apparatus
US2907914A (en) * 1954-05-26 1959-10-06 Magnetic Metals Company Electrically energized magnetic shield
US2936399A (en) * 1954-07-12 1960-05-10 Chromatic Television Lab Inc Color structure for cathode-ray tubes designed for polychrome image reproduction
US2951179A (en) * 1956-05-28 1960-08-30 Gen Electric Electron shield for post acceleration cathode ray tube
US2973454A (en) * 1955-06-07 1961-02-28 Gen Electric Color cathode ray image reproducing tube
US3051782A (en) * 1959-07-13 1962-08-28 Nat Video Corp Implosion panel spacing device
US3084217A (en) * 1960-08-18 1963-04-02 Zenith Radio Corp Television receiver with safety plate and mounting means

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2119559A (en) * 1935-07-25 1938-06-07 Bell Telephone Labor Inc Electron discharge device
US2123636A (en) * 1932-02-23 1938-07-12 Firm Fernseh Aktien Ges High-vacuum cathode ray tube
GB506418A (en) * 1936-08-25 1939-05-26 Lorenz C Ag Supporting means for braun tubes
US2343630A (en) * 1942-04-25 1944-03-07 Du Mont Allen B Lab Inc Shield for cathode ray tubes

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2123636A (en) * 1932-02-23 1938-07-12 Firm Fernseh Aktien Ges High-vacuum cathode ray tube
US2119559A (en) * 1935-07-25 1938-06-07 Bell Telephone Labor Inc Electron discharge device
GB506418A (en) * 1936-08-25 1939-05-26 Lorenz C Ag Supporting means for braun tubes
US2343630A (en) * 1942-04-25 1944-03-07 Du Mont Allen B Lab Inc Shield for cathode ray tubes

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2545524A (en) * 1945-08-29 1951-03-20 Rca Corp Schmidt television projection system
US2551790A (en) * 1949-04-01 1951-05-08 Rca Corp Positioning structure for cathode-ray tubes
US2756415A (en) * 1949-06-01 1956-07-24 Rca Corp Schmidt television projector arrangement
US2663011A (en) * 1949-07-06 1953-12-15 Sylvania Electric Prod Cathode-ray tube support
US2642550A (en) * 1950-01-19 1953-06-16 Nat Res Dev Electronic information storage device
US2602114A (en) * 1950-04-10 1952-07-01 Richard A Fisch Insulating ring and protective device for cathode-ray tubes
US2559353A (en) * 1950-07-25 1951-07-03 Richard A Fisch Mounting and protecting device for cathode-ray tubes
US2684477A (en) * 1951-05-21 1954-07-20 Richard A Fisch Mounting and insulating ring for cathode-ray and television tubes
US2907914A (en) * 1954-05-26 1959-10-06 Magnetic Metals Company Electrically energized magnetic shield
US2936399A (en) * 1954-07-12 1960-05-10 Chromatic Television Lab Inc Color structure for cathode-ray tubes designed for polychrome image reproduction
US2973454A (en) * 1955-06-07 1961-02-28 Gen Electric Color cathode ray image reproducing tube
US2951179A (en) * 1956-05-28 1960-08-30 Gen Electric Electron shield for post acceleration cathode ray tube
US2898586A (en) * 1956-06-25 1959-08-04 Sylvania Electric Prod Television apparatus
US3051782A (en) * 1959-07-13 1962-08-28 Nat Video Corp Implosion panel spacing device
US3084217A (en) * 1960-08-18 1963-04-02 Zenith Radio Corp Television receiver with safety plate and mounting means

Also Published As

Publication number Publication date
BE476954A (en)van)
GB638139A (en) 1950-05-31

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