US2884559A - Electron lens systems - Google Patents

Electron lens systems Download PDF

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Publication number
US2884559A
US2884559A US608532A US60853256A US2884559A US 2884559 A US2884559 A US 2884559A US 608532 A US608532 A US 608532A US 60853256 A US60853256 A US 60853256A US 2884559 A US2884559 A US 2884559A
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United States
Prior art keywords
deflection
lens
electrodes
electron
target
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
US608532A
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English (en)
Inventor
Jr Howard G Cooper
Marion E Hines
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.)
AT&T Corp
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Bell Telephone Laboratories Inc
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 BE559731D priority Critical patent/BE559731A/xx
Priority to NL108855D priority patent/NL108855C/xx
Priority to NL219031D priority patent/NL219031A/xx
Priority to US608532A priority patent/US2884559A/en
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to FR1173802D priority patent/FR1173802A/fr
Priority to DEW21119A priority patent/DE1162957B/de
Priority to GB25972/57A priority patent/GB821295A/en
Priority to CH4963357A priority patent/CH364046A/de
Application granted granted Critical
Publication of US2884559A publication Critical patent/US2884559A/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
    • H01J29/58—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
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/56—Arrangements for controlling cross-section of ray or beam; Arrangements for correcting aberration of beam, e.g. due to 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
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/70—Arrangements for deflecting ray or beam
    • H01J29/72—Arrangements for deflecting ray or beam along one straight line or along two perpendicular straight lines
    • H01J29/74—Deflecting by electric fields only

Definitions

  • The-present invention relates to electron-optical devices and more particularly toelectron discharge devices of the cathode ray type having means for correcting deflection defocusing of the electron beam.
  • an electron beam is shaped to. a desired configuration and directed toward a target structure where impinging electrons provide a visual or electrical indication thereof dependent on the particular application.
  • the electron beam is deflected by suitable electrostatic or electromagnetic means so as to strike the target surface at any one of a plurality of discrete areas, each providing a distinct output signal.
  • Suchdeflection presents serious problems in instances demanding minimum size and .precise uniformity of beam config l'lation at each point of impingement.
  • Deflection defocusing is inversely proportional to the length of the deflection field through which the electron beam must travel.
  • deflection defocusing increases with beam deflection angle so that the maximum required deflection angle should be small.
  • Increasing the length of tube from deflection system to target will assist in maintaining a small deflection angle and is thus advantageous within overall tube dimension requirements.
  • the'deflection defocusing problem may be reduced by increasing the length of deflection system and of beam travel from deflection system to target surface. In order to maintain a restricted overall tube length while satisfying these defocusing improvement factors, the portion of the tube containing the electron gun, lens and deflection system must be made shorter.
  • An eflective electron lens such as the einzelflens, serves to converge an electron beam to form a circular spot at the center of the target surface of a cathode ray tube.
  • a lens normally comprises a pair of circular apertured electrodes at a potential highly positive with re spect to the cathode and an intermediate circular aperr tured electrode at a potential intermediate the cathode potential and the potential of the outer lens electrodes.
  • This configuration is analogous to the spherical lens of light optics and is eifective to form a pencil shaped beam videfafldmairitain a uniformly small diameter .of the deflection system in an electron dissystem positioned in the beam path between the electron limited in cross section by the outer electrodes and subjected to the converging action of the low potential inner electrode in conjunction with the adjacent high potential outer electrodes.
  • a three electrode einzel lens as described cannot completely control deflection defocusing of a beam deflected in a single coordinate.
  • Such a lens employing slit apertures rather than circular apertures provides better control in a single coordinate, and two such lenses in turn will maintain a measure of uniformity in a beam deflected in two coordinates.
  • aberrations are greater in a slit aperture or cylindrical lens than in a spherical lens of the same focal length, and six electrodes comprise the two coordinate lens structure thus requiring a substantially greater tube length to accommodate the lens.
  • Ourinvntion as illustrated in the. specific embodiment described herein, satisfies the restricted lens length requirement to achieve reduced overall tube length while providing a, uniformlysmall spot diameter at any point on the target surface.
  • the lens system comprises a pair of outer electrodes having circular apertures, which electrodes enclose a second pair of electrodes having'elliptical apertures with their major axes parallel to opposite cartesian coordinates.
  • control electrodes be connected through a nonlinear circuit to a respective coordinate deflection voltage source.
  • Fig. 1 is adi agrammatic representation'of a barrier grid storage tube incorporating one specific illustrative embodiment 'of this invention
  • Fig. '2 is a schematic diagram of one illustrative embodi'ment includinga;'perspective view of the lens system for theemb'o'dirhento'f Fig. 'lgreatly enlarged in relation to adjacent elements;
  • Figs. '3 andf4 are diagrammatic views of an undeflected and vertically deflected electron beam, respectively,"focused at the target structure;
  • Figs 5, 6' and 7 are views of a quadrant of the target structure "illustrating respectively the impinging electron beam without defocusing'correction, with defocusing corre'cticfa'n utilizing "an "einzel lens with circular apertured electrodes, and with defocusing correction in accordance theernjbo'dimentof"Fig. 1'; of invention.
  • the tube 10 may advantageouslyfcomprise within an evacuated envelope, such as glass, an electron gun including a cathode 11,"hea'ter 12, control grid 13, accelerating anode 14, focusing electrodes 15 defining an electron lens, deflectron plates 16 and 17, “a collector electrode 18, ashield l9, and'a targetassembly 20.
  • the 'target assembly 20 IS a sandwich of three elements including a back plate 22, a dielectrie sheet-23, and a barrier grid 24 positioned directly in front of the dielectric sheet 23.
  • the dielectric sheetf23 holds an electrostatic charge deposited on its surface by the electron beam for extended periods of time, thereby performing the storage function the tube.
  • 2 2 is insulated from the 1 may be varied to join fl ijs a??? an fiaie by the electron-beam. Ihe'eharge deposited'atan w cre'te' area of the dielectric sheet 23 is subsequently dtectedby returning the electron beam to the discrete area.
  • the sizeand' proximityof discrete-"storage areas on a given'ltarget surface are”dependent in part onthe size, .ntensity .2 and uniformity .of theiin'cident electron beam.
  • the beam isfnecessarily deflected to reach anyone of die discrete storage areas, but inherent in electrostatic deflection is a certain measure of beam defocusing which tends to restrict the number of possible discrete storage areas.
  • an electron beam converges to a point 37 on a target 36.
  • a cross section of the beam preceding the vertical deflection plates 35 is substantially circular as is indicated by the shaded area. With equal potentials on vertical deflection plates 35, the beam is unafiected thereby and passes to its focal point 37.
  • Fig. 4 the same electron beam is deflected vertically by a potential difference applied between the plates 35.
  • the beam now is subjected to a focusing eifect by the deflection field tending -to produce 'a-cross over of electrons in the vertical plane prior to reaching the target 36 and resulting in an oblong rather "than circular target impingement area 38 which is appreciably enlarged over the impingement area of Fig. 3.
  • the deflection plates acting as ⁇ a cylindrical converging lens tend to restrict the magnitude'of storage in the barrier g'rid tube, since discrete st orage areas must be spaced far enough apart to prevent possible overlap dueto the enlarged beam cross section toward the target extremities. Such overlap would tend to destroy the information stored at adjacent areas of the dielectric surface.
  • ancle'ctro'n lens arrangement in accordance with this invention will satisfy the requirements of uniformly small spot diameter at any deflection angle and will permit a reduction in overall tube length without increasing the deflection angle in comparison with other arrangements known in the art.
  • Fig.2 there is shown the principal elements of the embodiment of Fig. l whichprovide the desired deflection defocu's'ing'correction in'a twocoordinate deflection system.
  • the electron lens there depicted comprises a first limiting electrode 25 having a'circula'r aperture therein and placed at a high positive potential with respect to the cathode.
  • Electrodes-2'6 and 27 have elliptical apertures and each obtaina variable potential from respective coordinate "deflection voltage "sources through nonlinear circuits whichpotential-is advantageously between that of the cathode "a'rid'th'at :of electrode 25.
  • electrode 26 having the minoraiiis'ofits elliptical aperture in a vertical'plane, is connected through nonlinear circuit 31 to the vertical d'e'flection system input circuit 32.
  • electrode 27 has its minor elliptical axis in 'a horizontal plane and is connected through nonlinear circuit 33 to the horizontal deflection system input circuit 34.
  • Electrode 28 completes theelcctron lens and resembles electrode 25 in configuration and applied potential.
  • electrodes 25, 26, 27 and 28 coact to'focus the'electron beam, formed from electrons emitted by thetubcs thermionic cathode, in a spot of minimum size at the center of the target screen.
  • the focusing action'of these electrodes in this instance is comparable to that of one or more spherical-surfaced opticallenscs and to the well known einzel electrostatic lens
  • the focusing action ' is "effected by maintaining a potentialdifferen'cebetween adjacent electrodes. It is also'infiue'nced tosome' extent by the mutual separation -of tlie electrodes.
  • the lens electrodes are adjustable without changing their physical arrangement, just by changing the potentials and relative potentials of the constituent electrodes.
  • Each elliptical apertured lens electrode zs and 26 bears similarity in operation to the cylindrical optical lens 5. in which equal convergence or divergence may be eflected between-parallel planes, the major axis of the ellipse being perpendicular to the parallel planes.
  • a pure cylin drical electron lens is one dimensional and is formed by a pair of coplanar plates of infinite length separated to form a slit of infinite length across which the electrostatic focusing field is developed. Obviously the slit length is dictated by maximum permissible tube proportions so that in operation the ends are closed to form a compromise rectangular aperture. *Such a compromise, however, results in interaction between focus control in the desired and perpendicular planes.
  • the cylindrical focusing efiect of the deflection plates 16 and 17 will distort the beam such that a circular spot on the target becomes elliptical with deflection of the beam away from the center of the target.
  • the distortion due to the deflection system alone, as seen in Fig. 5, increases proportionate to the deflection angle and, in fact, proportionate to the square of the mean deflection angle.
  • Fig. 6 the deflected beam distortion is shown which results from the employment of an einzcl lens with circular apertured electrodes preceding the deflection plates in the tube structure.
  • the spherical converging action of the electrostatic field developed in such a lens prefocuses the beam'to compensate for the cylindrical lens eflect of the deflection plates.
  • the distortion at the target is corrected to some extent.
  • a spherical lens arrangement introduces a pencil shaped beam to the deflection system and cannot completely correct for the one-dimensional deflection defocusing eflects on such a beam configuration at all points on the target. Correction will be least when the beam is deflected to maximum in one coordinate and undeflected in the other coordinate as at points 60 and 61 in Fig. 6.
  • an einzcl lens comprising three slit apertured electrodes for each deflection coordinate may overcome the first difliculty when coupled with dynamic correction circuitry, but the length of tube required to accommodate six spaced electrodes is prohibitive in the limited tube dimensions of many storage tube applications. Compensating for this lens space requirement by shortening the deflection plates and their distance from the target would further aggravate the deflection defocusing problem as described hereinbefore. Additionally, aberrations are greater in the slit electrode cylindrical lens making it less attractive in this respect than the circularly apertured spherical lens.
  • Fig. 7 illustrates the results obtained utilizing the arrangement in accordance with the embodiment of this invention illustrated in Fig. 2.
  • a spot size compatible with the rigid requirements of the barrier grid tube for large scale storage is obtained at the target center, and the identical spot size is maintained at every deflected beam position about the target surface.
  • the unique crossed elliptical lens arrangement utilizes a single elliptical lens electrode in each coordinate serving to converge the beam only in that coordinate and coacting on an undeflected beam to converge the beam at the center of the target.
  • An electrical circuit provided between the lens and deflection systems weakens the electrostatic field at each elliptical electrode as its corresponding deflection plates 6. are energized.
  • the dynamic voltage applied to each lens is proportional to the square of the voltage difierence between the deflection plates which act in that plane.
  • Fig. 2 One manner of accomplishing this dynamic field variation is shown in Fig. 2 wherein balanced push-pull deflection is utilized.
  • a sample of the vertical deflection voltage from source 32 is applied to the grids of parallel connected vacuum tubes 40 and 41 of nonlinear circuit 31.
  • the grid voltages vary in a balanced manner, but the sum of the plate currents should, to a first approximation, vary as the square of the deflection voltage.
  • the combined plate current of tubes 40 and 41 produces a voltage across resistance 42 which varies in the desired manner and is applied to the electrode 26.
  • a similar circuit is provided to control electrode 27 in accordance with the horizontal deflection voltage. As shown in Fig. 2 the focus electrodes 26 and 27 are operated at a positive potential to obtain the basic focusing. If negative voltages are employed, a phase inverter stage may be utilized to'weaken the electrostatic fields at electrodes 26 and 27 when deflection voltages are applied.
  • the crossed elliptical lens with electrostatic fields compensated dynamically as described serves to converge the beam to a uniform small spot diameter at any deflected position. Also, with only four electrodes comprising the lens structure a minimum tube diameter and length is achieved.
  • Aperture diameter Inch Electrode 25 .048 Electrode 28 .075 Electrodes 26, 27-
  • Electrodes 25 and 28 were placed at a potential 1000 volts above that of the cathode. Electrodes 26 and 27 are placed at 420 volts and 470 volts above that of the cathode, respectively, to obtain initial undeflected focusing in both horizontal and vertical coordinates. With these values, of the electron beam will pass through a square .007 inch on a side. Thus a beam diameter at the target of approximately .007 inch was obtained, which diameter remained constant and uniform at every deflected position of the beam on the target.
  • a cathode ray tube comprising means for projecting; a beam of electrons along a path, means for deflecting the projected beam in mutually perpendicular directions, and means for focusing said beam prior to deflection comprising a pair of equipotential control electrodes having circular apertures and a pair of focus electrodes having apentures of uniformly varying, width elongated in mutually perpendicular directionsparallel to respective deflection directions, eachof said focus electrodes being positioned between one of said control electrodes and the other of said focus electrodes and coupled through a nonlinear circuit to the source of deflection voltage.
  • An electron discharge device comprising target means, meansfor providing an electron beam and means for deflecting said electron beam over said target means including means for producing a pair of mutually perpendicular deflection fields with separate coordinate deflection voltage source's, an electron optical system comprising a pair of control electrodes having circular apertures aligned. to pass a portion of said electron beam,v a first focus electrode having an elliptical aperuire elongated perpendicular to one of said deflection'fields and a second focus. electrode having an elliptical aperture elongatedpen pendicular to the other of. said deflection fields, said focus electrodes being positioned between said control electrodes.
  • p v r 3 A cathode ray device in accordance with claim 1 wherein said focus electrode apertures are substantially References inthe file of this patent UNITED STATES PATENTS 2,103,645

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  • Electron Beam Exposure (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
US608532A 1956-09-07 1956-09-07 Electron lens systems Expired - Lifetime US2884559A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
BE559731D BE559731A (xx) 1956-09-07
NL108855D NL108855C (xx) 1956-09-07
NL219031D NL219031A (xx) 1956-09-07
US608532A US2884559A (en) 1956-09-07 1956-09-07 Electron lens systems
FR1173802D FR1173802A (fr) 1956-09-07 1957-04-29 Systèmes de lentilles électroniques
DEW21119A DE1162957B (de) 1956-09-07 1957-05-06 Elektronenlinsensystem zur Korrektur der Strahlenbuendelung in einer Kathodenstrahlroehre
GB25972/57A GB821295A (en) 1956-09-07 1957-08-16 Improvements in or relating to electron discharge devices incorporating electron lenses
CH4963357A CH364046A (de) 1956-09-07 1957-08-21 Elektronenlinsenanordnung in einem Elektronenstrahlgerät

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US608532A US2884559A (en) 1956-09-07 1956-09-07 Electron lens systems

Publications (1)

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US2884559A true US2884559A (en) 1959-04-28

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US608532A Expired - Lifetime US2884559A (en) 1956-09-07 1956-09-07 Electron lens systems

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US (1) US2884559A (xx)
BE (1) BE559731A (xx)
CH (1) CH364046A (xx)
DE (1) DE1162957B (xx)
FR (1) FR1173802A (xx)
GB (1) GB821295A (xx)
NL (2) NL219031A (xx)

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2988660A (en) * 1958-07-02 1961-06-13 Gen Dynamics Corp Electro optical system in a cathode ray tube
US3040205A (en) * 1960-05-31 1962-06-19 Harold R Walker Electrostatic vidicon
US3142779A (en) * 1957-12-12 1964-07-28 Csf Electrostatic deflection arrangement for electron tubes
US3258402A (en) * 1960-02-26 1966-06-28 Itt Electric discharge device for producing interactions between nuclei
US3371206A (en) * 1964-02-04 1968-02-27 Jeol Ltd Electron beam apparatus having compensating means for triangular beam distortion
US3437870A (en) * 1965-11-03 1969-04-08 Minnesota Mining & Mfg Scan line masking system
US3497763A (en) * 1967-12-22 1970-02-24 Philips Corp Grid to compensate for astigmatic quadrupolar lens
US3544836A (en) * 1966-04-27 1970-12-01 Forgflo Corp Slot stigmator
US3579010A (en) * 1968-10-31 1971-05-18 Philco Ford Corp Elongated aperture electron gun structure for flat cathode-ray tube
US3702950A (en) * 1969-04-24 1972-11-14 Matsushita Electronics Corp Electrostatic focussing-type television picture tube utilizing a plurality of metal disks
US3792303A (en) * 1970-10-30 1974-02-12 A Albertin Cathode-ray tube with deflection amplification and post-deflection acceleration
USB381074I5 (xx) * 1971-07-28 1975-01-28
US3881136A (en) * 1972-03-24 1975-04-29 Philips Corp Cathode ray tube comprising a non-rotationally symmetrical element
US3887834A (en) * 1968-11-09 1975-06-03 Philips Corp Cathode-ray tube having an electric cylinder lens for the dynamic correction of electrostatic deflection defocusing
EP0033805A1 (en) * 1980-01-30 1981-08-19 Control Data Corporation An electrostatic lens assembly for a charged particle beam tube and a method of operating the same
US4319163A (en) * 1980-06-30 1982-03-09 Rca Corporation Electron gun with deflection-synchronized astigmatic screen grid means
US4322742A (en) * 1976-11-30 1982-03-30 Sony Corporation Method and apparatus for improving the sharpness of a video picture
US4322655A (en) * 1977-12-28 1982-03-30 Tokyo Shibaura Denki Kabushiki Kaisha Beam index color cathode ray tube
US4583024A (en) * 1984-02-21 1986-04-15 Rca Corporation Color picture tube having an inline electron gun with built-in stigmator
US4731563A (en) * 1986-09-29 1988-03-15 Rca Corporation Color display system
EP0275191A2 (en) * 1987-01-14 1988-07-20 RCA Thomson Licensing Corporation Color cathode-ray tube having a three-lens electron gun
US4887009A (en) * 1986-02-12 1989-12-12 Rca Licensing Corporation Color display system

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1165002A (en) * 1965-09-25 1969-09-24 Emi Ltd Improvements relating to Cathode Ray Tubes and Focusing and Deflecting Arrangements Therefor.
US3952224A (en) * 1974-10-04 1976-04-20 Rca Corporation In-line electron guns having consecutive grids with aligned vertical, substantially elliptical apertures
EP0014922A1 (de) * 1979-02-22 1980-09-03 International Standard Electric Corporation Elektronenstrahlerzeugungssystem
JPS55136442A (en) * 1979-04-10 1980-10-24 Toshiba Corp Electron gun
JPS5750749A (en) * 1980-09-11 1982-03-25 Matsushita Electronics Corp Electromagnetic deflection type cathode ray tube

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US2103645A (en) * 1932-12-20 1937-12-28 Schlesinger Kurt Braun tube
US2449524A (en) * 1944-11-27 1948-09-14 Us Sec War Oscilloscope device
US2572858A (en) * 1947-06-03 1951-10-30 Sylvania Electric Prod Electron optical system
US2572861A (en) * 1947-06-03 1951-10-30 Sylvania Electric Prod Deflection system for cathode-ray tubes
FR1049041A (fr) * 1952-01-11 1953-12-28 Radiotechnique Perfectionnement aux tubes à rayons cathodiques
US2698400A (en) * 1947-06-03 1954-12-28 Sylvania Electric Prod Generator for dynamic focusing of cathode ray tubes

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2111231A (en) * 1934-06-27 1938-03-15 Radio Patents Corp Recording device
DE902888C (de) * 1951-05-23 1954-01-28 Sueddeutsche Lab G M B H Elektronenstrahl-Oszillograph oder Fernsehroehre

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2103645A (en) * 1932-12-20 1937-12-28 Schlesinger Kurt Braun tube
US2449524A (en) * 1944-11-27 1948-09-14 Us Sec War Oscilloscope device
US2572858A (en) * 1947-06-03 1951-10-30 Sylvania Electric Prod Electron optical system
US2572861A (en) * 1947-06-03 1951-10-30 Sylvania Electric Prod Deflection system for cathode-ray tubes
US2698400A (en) * 1947-06-03 1954-12-28 Sylvania Electric Prod Generator for dynamic focusing of cathode ray tubes
FR1049041A (fr) * 1952-01-11 1953-12-28 Radiotechnique Perfectionnement aux tubes à rayons cathodiques

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3142779A (en) * 1957-12-12 1964-07-28 Csf Electrostatic deflection arrangement for electron tubes
US2988660A (en) * 1958-07-02 1961-06-13 Gen Dynamics Corp Electro optical system in a cathode ray tube
US3258402A (en) * 1960-02-26 1966-06-28 Itt Electric discharge device for producing interactions between nuclei
US3040205A (en) * 1960-05-31 1962-06-19 Harold R Walker Electrostatic vidicon
US3371206A (en) * 1964-02-04 1968-02-27 Jeol Ltd Electron beam apparatus having compensating means for triangular beam distortion
US3437870A (en) * 1965-11-03 1969-04-08 Minnesota Mining & Mfg Scan line masking system
US3544836A (en) * 1966-04-27 1970-12-01 Forgflo Corp Slot stigmator
US3497763A (en) * 1967-12-22 1970-02-24 Philips Corp Grid to compensate for astigmatic quadrupolar lens
US3579010A (en) * 1968-10-31 1971-05-18 Philco Ford Corp Elongated aperture electron gun structure for flat cathode-ray tube
US3887834A (en) * 1968-11-09 1975-06-03 Philips Corp Cathode-ray tube having an electric cylinder lens for the dynamic correction of electrostatic deflection defocusing
US3702950A (en) * 1969-04-24 1972-11-14 Matsushita Electronics Corp Electrostatic focussing-type television picture tube utilizing a plurality of metal disks
US3792303A (en) * 1970-10-30 1974-02-12 A Albertin Cathode-ray tube with deflection amplification and post-deflection acceleration
US3866081A (en) * 1971-07-28 1975-02-11 Philips Corp Cathode ray gun having first and second grids with orthogonal apertures
USB381074I5 (xx) * 1971-07-28 1975-01-28
US3919583A (en) * 1971-07-28 1975-11-11 Philips Corp Electron gun with grid and anode having orthogonal elongated apertures
US3881136A (en) * 1972-03-24 1975-04-29 Philips Corp Cathode ray tube comprising a non-rotationally symmetrical element
US4322742A (en) * 1976-11-30 1982-03-30 Sony Corporation Method and apparatus for improving the sharpness of a video picture
US4322655A (en) * 1977-12-28 1982-03-30 Tokyo Shibaura Denki Kabushiki Kaisha Beam index color cathode ray tube
EP0033805A1 (en) * 1980-01-30 1981-08-19 Control Data Corporation An electrostatic lens assembly for a charged particle beam tube and a method of operating the same
US4319163A (en) * 1980-06-30 1982-03-09 Rca Corporation Electron gun with deflection-synchronized astigmatic screen grid means
US4583024A (en) * 1984-02-21 1986-04-15 Rca Corporation Color picture tube having an inline electron gun with built-in stigmator
US4887009A (en) * 1986-02-12 1989-12-12 Rca Licensing Corporation Color display system
US4731563A (en) * 1986-09-29 1988-03-15 Rca Corporation Color display system
EP0275191A2 (en) * 1987-01-14 1988-07-20 RCA Thomson Licensing Corporation Color cathode-ray tube having a three-lens electron gun
EP0275191A3 (en) * 1987-01-14 1989-06-07 Rca Licensing Corporation Color cathode-ray tube having a three-lens electron gun

Also Published As

Publication number Publication date
NL108855C (xx)
BE559731A (xx)
FR1173802A (fr) 1959-03-03
NL219031A (xx)
CH364046A (de) 1962-08-31
DE1162957B (de) 1964-02-13
GB821295A (en) 1959-10-07

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