US2773212A - Electron gun - Google Patents

Electron gun Download PDF

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Publication number
US2773212A
US2773212A US374240A US37424053A US2773212A US 2773212 A US2773212 A US 2773212A US 374240 A US374240 A US 374240A US 37424053 A US37424053 A US 37424053A US 2773212 A US2773212 A US 2773212A
Authority
US
United States
Prior art keywords
screen
cathode
grid
anode
picture
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
US374240A
Other languages
English (en)
Inventor
James A Hall
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.)
CBS 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 BE530971D priority Critical patent/BE530971A/xx
Priority to NLAANVRAGE7909276,A priority patent/NL189231B/nl
Priority to NL96222D priority patent/NL96222C/xx
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US374240A priority patent/US2773212A/en
Priority to DEW14347A priority patent/DE1015948B/de
Priority to GB22450/54A priority patent/GB761008A/en
Priority to FR1109867D priority patent/FR1109867A/fr
Application granted granted Critical
Publication of US2773212A publication Critical patent/US2773212A/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
    • H01J29/46—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
    • H01J29/58—Arrangements for focusing or reflecting ray or beam
    • H01J29/62—Electrostatic lenses
    • 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
    • H01J29/84—Traps for removing or diverting unwanted particles, e.g. negative ions, fringing electrons; Arrangements for velocity or mass selection

Definitions

  • the electron beams in cathode-ray tubes are'proj'ected by an assemblage ot electrodes known as ⁇ an electron gun such as is diagrammed in Fig. l which comprises ⁇ a ⁇ heated cathode l having a control electrode 2 enclosing its electron-emissive end-portion except forl an aperture4 3.
  • Facing the control electrode 2 is ascreen-electrode 4 comprising a disc 5 with an aperture 6 aligned with aperture 3,. and a cylindrical wall which may have a rolled Aedge 7.
  • Facing the wall 7 is the circular edge of another cylindrical member 9 which may be .joined tocylindrical member 13 by flanges 11 and 12.
  • the member 13 is -closed at ⁇ its remote end by aV disc with an aperture ⁇ 17 ⁇ located on the axis of member 13.
  • the rim of the screen-grid electrodewally'? and :adjacent edge of member 9 may be slanted at an angle of abouti() to l3 degrees relative to theV plane perpen- (dicular to the axis of the screen electrode 4.
  • ⁇ cylindrical sleeve 16 Surrounding the gap between .cylinders 13 and11'4 is Va larger ⁇ cylindrical sleeve 16 called the focussingl electrode.
  • Sleeve 16 is insulatingly supported coaxiallyyand :approximately symmetricallyrelative to the gap; between *cylinders 13 and 1e. In some designs, ⁇ af-similarly lo- Ycatedring or discwith centrally located-aperture is lprovidedinstead of the sleeve 16 toproduce thefocussing lteld.
  • the outer end of'cylinder 14 customarily has a wide flange which'is provided with springs 15 of flexible metal which engage the walls of thecathode-ray tube and assist in ⁇ positioning 'the cathode-ray gunjstructure ⁇ centrally, therein.
  • the bias voltage on control electrode 2. ⁇ isdmade ⁇ manually variable to enable control of picture brightness by varying the current in the electron beam., ⁇ The potential needed for cylinder 16 to maintain the best4 spot focus, hereinaliter called they focus voltage, becomes rapidly more negative as the picture brightness, Vand ⁇ hence beam current, is increased.
  • This'tocussing voltage is "customarily derived from the supply ywhich furnishes 250 to ⁇ 350volts D. @for anode power for ⁇ the receiving available may be insulrcient to ⁇ maintain the best focus with variation or picture brightness.
  • control electrode 2 is modu- -lated by the signal from the'video amplifier ofthe television receiver to vary the brightness of the fluorescent spot on the picture ⁇ tube screen by ⁇ varying t Kunststoffeam current asi-each picture element is scanned;
  • tubes .using electrostatically focussed ⁇ guns of the prior: art- ⁇ the ,size of the uorescent spot becomes ⁇ rapidly: larger: .and
  • cathode-ray tubes must fit a wide variety of different television receivers, and the magnitudes of the screen-grid (electrode 4) and anode (electrodes 9, 13, 14) supply voltages varies widely between television sets of different manufacturers. Typical ranges for these voltages are 275 to 500 volts for the screen-grid voltage and l0 to 18 kilovolts for the'anode voltage. Furthermore, the picture brightness requirements considered necessary by various receiver manufacturers range from 12 to 70 foot lamberts.
  • the magnetic field impressed near the screen-grid 4 as part of the ion-trapping device is of non-uniform intensity across the region traversed by the electron beam; in electron guns of prior design, the cross section of the beam is distorted from a true circle, the shape of the light spot produced on the picture screen is distorted from a circle and picture resolution is degraded. Both the uniformity and strength of this magnetic field vary between sets of different manufacture, so that a compensating non-uniform electric field cannot be used to correct this beam distortion.
  • Still another object is to produce a cathode-ray gun in which focussing in the electron lens comprising the screen' grid and the first anode is reduced virtually to zero.
  • Still another object is to produce a cathode-ray gun in which the percentage of the electrons emitted by the 'cathode which arrive at the picture screen is little affected by variations in the anode voltage or the screen-grid voltage.
  • Yet another object is to provide a cathode-ray gun in which larger tolerances in the symmetry of the electron lens comprising the screen-grid first anode may be permitted than in cathode-ray guns of the prior art.
  • Yet another object is toproducea cathod'efraygun ⁇ in which the focussing effect at ⁇ the rst electronglens, adjafl cent1 the screen-grid electrode, is reduced and the focus ⁇ sing effect of the second electron lens, between theanode cylinders and focussing electrode, is normal;
  • Figure 1 isa schematic view showing the relation ofthe cathode-ray gun embodying the principles of my invention to the otherstructural elements'A of a cathode-ray tube.
  • FIG. 3 Yis asimilar view ⁇ of a cathode-ray gun embodyingthe principles of my invention
  • the cathode 1"c ⁇ ornpr ⁇ ise ⁇ s a" metal cylinder 30 having a cupped end 33fsurfaced ⁇ with thefr'r'n ionically-emissive material which is heated byian'electri'cal heater-winding 23.
  • the cathode is supported by a ⁇ ceramic collar from" the control electrode 2, which has its end'facing cuppedend 22 closed exceptfor ⁇ central'"aperture3. ⁇
  • the distance from the emissive surface on cathode '1"t ⁇ o the aperture 3 isabout 0.01 D; the other important dirnen-A sions Vof-cathode 1 and control electrode 2 are tabulatedA below.
  • cathode 1 may he grounded; control electrode 2 may be impressed with signal voltages and with a variable negative bias to control brightness of the picture on Screen 19; screen-grid electrode 4 in section of a cathodewith a Xed position voltage usually between 250 and 500 volts; electrodes 9, 13 and 14 with the anode supply voltage of 10 to 18 kilovolts; and sleeve 16 with a focusireage usually variable over a portion of the range from l00 to +450 volts.
  • Non-uniformity and astigmatism in the cathode-ray beam arising from the departures from uniformity in the magnetic field of the ion-trap magnet are greatly reduced when the focussing effect of the screen-grid-tofirst-anode lens is reduced by my construction.
  • the same tube may be marketed for use in makes of receiver having anode voltages from 10 to 18 kv. and screen-grid voltages from 250 to 500 volts, Vwhich of our present knowledge includes all the receiver designs which are now sold or have been sold for useY with low voltage electrostatically focussed cathode-ray tubes.
  • An electron gun comprising a control electrode and a screen-grid electrode, said electrodes comprising coaxialcylinders of inside diameter D having diaphragms normal to their common axis and with apertures lying on said axis, an electron source on Isaid axis on the side of said control electrode aperture remote from said screen-grid electrode, a rim of said screen-grid ⁇ remote from said con- -trol electrode lying in a first plane oblique to said axis, the major length of said screen-grid being not over .55 D, a first anode cylinder of diameter D and having a rim adjacent to said screen-grid lying in a secon-d plane parallel 4to said first plane and separated therefrom by a gap substantially ⁇ 0.20 D t-o 0.24 D wide, and an electron lens of substantial focussing po'wer at ⁇ the other end of said first anode cylinder.
  • An electron gun compri-sing a control electrode and a screen-grid electrode, said electrodes comprising coaxial cylinders of inside diameter D having diaphragms normal to their common axis ⁇ and ⁇ with apertures lying -onsaid yaxis, an electron source on said axis on the side of said control electrode aperture remote from said screengrid electrode, a rim of said screen-grid remote from said control electrode lying in a first plane, the length of said screen-grid being not over .44 D, a first anode cylinder of diameter D and having a rim adjacent to s-aid screengrid lying in .a second plane pa-rallel to said first plane and separated therefrom -by a gap of about .20 D wide and an electron lens of substantial focusing power at the other end of said first Ianode cylinder.

Landscapes

  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Eye Examination Apparatus (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
US374240A 1953-08-14 1953-08-14 Electron gun Expired - Lifetime US2773212A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
BE530971D BE530971A (nl) 1953-08-14
NLAANVRAGE7909276,A NL189231B (nl) 1953-08-14 Inrichting voor het ten behoeve van een medische diagnose kopieren van een op een drager geregistreerd stralingsbeeld.
NL96222D NL96222C (nl) 1953-08-14
US374240A US2773212A (en) 1953-08-14 1953-08-14 Electron gun
DEW14347A DE1015948B (de) 1953-08-14 1954-07-03 Elektronenstrahlerzeugungssystem fuer eine Kathodenstrahlroehre, insbesondere fuer Fernsehzwecke
GB22450/54A GB761008A (en) 1953-08-14 1954-08-03 Improvements in or relating to cathode ray tubes
FR1109867D FR1109867A (fr) 1953-08-14 1954-08-05 Canon à électrons

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US374240A US2773212A (en) 1953-08-14 1953-08-14 Electron gun

Publications (1)

Publication Number Publication Date
US2773212A true US2773212A (en) 1956-12-04

Family

ID=23475915

Family Applications (1)

Application Number Title Priority Date Filing Date
US374240A Expired - Lifetime US2773212A (en) 1953-08-14 1953-08-14 Electron gun

Country Status (6)

Country Link
US (1) US2773212A (nl)
BE (1) BE530971A (nl)
DE (1) DE1015948B (nl)
FR (1) FR1109867A (nl)
GB (1) GB761008A (nl)
NL (2) NL96222C (nl)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2905848A (en) * 1957-10-18 1959-09-22 Philco Corp Cathode ray tube gun structure
US2911563A (en) * 1957-04-24 1959-11-03 Westinghouse Electric Corp Electrostatic lens and deflection system
US2922072A (en) * 1957-12-05 1960-01-19 Sylvania Electric Prod Image reproduction device
US2935635A (en) * 1957-11-18 1960-05-03 Philco Corp Cathode ray tube display system
DE1097045B (de) * 1957-12-27 1961-01-12 Westinghouse Electric Corp Strahlerzeugungssystem fuer Kathodenstrahlroehren
US3200469A (en) * 1960-01-28 1965-08-17 Rca Corp Spherical grids and methods of making same
US3374385A (en) * 1963-07-10 1968-03-19 Rca Corp Electron tube cathode with nickel-tungsten alloy base and thin nickel coating
US8969794B2 (en) 2013-03-15 2015-03-03 1St Detect Corporation Mass dependent automatic gain control for mass spectrometer
US9035244B2 (en) 2013-03-11 2015-05-19 1St Detect Corporation Automatic gain control with defocusing lens

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1194067B (de) * 1960-04-13 1965-06-03 Rca Corp Strahlerzeugungssystem fuer eine Kathoden-strahlroehre
BE624426A (nl) * 1961-11-07

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2484721A (en) * 1942-03-14 1949-10-11 Cossor Ltd A C Electrode gun such as is used in cathode-ray tubes
US2496127A (en) * 1947-02-05 1950-01-31 Rca Corp Electron gun for cathode-ray tubes
US2515305A (en) * 1946-01-24 1950-07-18 Rca Corp Electromagnet
US2638559A (en) * 1952-01-19 1953-05-12 Nat Video Corp Electrostatic lens for cathode-ray tubes
US2680204A (en) * 1950-11-30 1954-06-01 Rca Corp Gun structure

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH224295A (de) * 1941-09-30 1942-11-15 Philips Nv Elektrische Einrichtung mit einer Braunschen Röhre.

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2484721A (en) * 1942-03-14 1949-10-11 Cossor Ltd A C Electrode gun such as is used in cathode-ray tubes
US2515305A (en) * 1946-01-24 1950-07-18 Rca Corp Electromagnet
US2496127A (en) * 1947-02-05 1950-01-31 Rca Corp Electron gun for cathode-ray tubes
US2680204A (en) * 1950-11-30 1954-06-01 Rca Corp Gun structure
US2638559A (en) * 1952-01-19 1953-05-12 Nat Video Corp Electrostatic lens for cathode-ray tubes

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2911563A (en) * 1957-04-24 1959-11-03 Westinghouse Electric Corp Electrostatic lens and deflection system
US2905848A (en) * 1957-10-18 1959-09-22 Philco Corp Cathode ray tube gun structure
US2935635A (en) * 1957-11-18 1960-05-03 Philco Corp Cathode ray tube display system
US2922072A (en) * 1957-12-05 1960-01-19 Sylvania Electric Prod Image reproduction device
DE1097045B (de) * 1957-12-27 1961-01-12 Westinghouse Electric Corp Strahlerzeugungssystem fuer Kathodenstrahlroehren
US3200469A (en) * 1960-01-28 1965-08-17 Rca Corp Spherical grids and methods of making same
US3374385A (en) * 1963-07-10 1968-03-19 Rca Corp Electron tube cathode with nickel-tungsten alloy base and thin nickel coating
US9035244B2 (en) 2013-03-11 2015-05-19 1St Detect Corporation Automatic gain control with defocusing lens
US8969794B2 (en) 2013-03-15 2015-03-03 1St Detect Corporation Mass dependent automatic gain control for mass spectrometer
US9472388B2 (en) 2013-03-15 2016-10-18 1St Detect Corporation Mass dependent automatic gain control for mass spectrometer

Also Published As

Publication number Publication date
NL189231B (nl)
GB761008A (en) 1956-11-07
DE1015948B (de) 1957-09-19
BE530971A (nl)
FR1109867A (fr) 1956-02-02
NL96222C (nl)

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