US3755703A - Electron gun device for color tube - Google Patents

Electron gun device for color tube Download PDF

Info

Publication number
US3755703A
US3755703A US00815941A US3755703DA US3755703A US 3755703 A US3755703 A US 3755703A US 00815941 A US00815941 A US 00815941A US 3755703D A US3755703D A US 3755703DA US 3755703 A US3755703 A US 3755703A
Authority
US
United States
Prior art keywords
cathodes
grids
apertures
grid
beam generating
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
US00815941A
Other languages
English (en)
Inventor
K Ueno
S Miyaoka
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.)
Sony Corp
Original Assignee
Sony 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 claimed from JP2459068A external-priority patent/JPS512787B1/ja
Priority claimed from JP2458968A external-priority patent/JPS512789B1/ja
Application filed by Sony Corp filed Critical Sony Corp
Application granted granted Critical
Publication of US3755703A publication Critical patent/US3755703A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
    • 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
    • H01J31/10—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes
    • H01J31/20—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes for displaying images or patterns in two or more colours
    • H01J31/201—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes for displaying images or patterns in two or more colours using a colour-selection electrode
    • H01J31/203—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes for displaying images or patterns in two or more colours using a colour-selection electrode with more than one electron beam
    • H01J31/206—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes for displaying images or patterns in two or more colours using a colour-selection electrode with more than one electron beam with three coplanar electron beams
    • 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
    • H01J29/50—Electron guns two or more guns in a single vacuum space, e.g. for plural-ray tube
    • H01J29/503—Three or more guns, the axes of which lay in a common plane

Definitions

  • Equalization preferably is obtained y making one or more of the apertures in the first and second References Clted grids of a diameter different from that of the other ap- UNITED STATES PATENTS ertures, or by making the distances of one or more of 2,726,347 12 1955 Benway 313/70 c the at d s fr m th grids different from the corre- 2,735,031 2/1956 Woodbridge.... 313/70 C sponding distances of the other cathodes, or by a com- 2,825,845 3/1958 Jonker et a1. 313/70 C X bination of both of these arrangements.
  • This invention relates to an electron gun device, and particularly to an electron gun device for a single-gun, plural-beam type of color television picture tube.
  • the cutoff voltages of the cathodes are not equal to one another.
  • the result of this imbalance is that the gamma characteristics of the three colors in the picture produced by the tube are difierent and the colors are not natural.
  • a major object of this invention is to provide a plural-cathode electron gun device whose cathodes have the same cutoff voltages.
  • a further object of the invention is to provide a relatively simple and inexpensive means for equalizing the cutoff voltages of such cathodes.
  • the foregoing objects are met by the provision of means for equalizing the cathode cutoff voltages by equalizing the intensity of the electric field reaching the cathodes from the grids of the electron gun.
  • the equalization means selectively limits the amount of flux reaching one or more of the cathodes.
  • equalization is accomplished by making one or more of the apertures in the first and second grids of a diameter difi'erent from that of the other apertures, or by making the distances of one or more of the cathodes from the grids different from the corresponding distances of the other cathodes, or by a combination of both of these arrangements.
  • FIG. 1 shows a typical color television picture tube in which the electron gun of this invention can be used
  • FIG. 2 is an enlarged, broken-away partially schematic view of a portion of the electron gun shown in FIG. 1;
  • FIGS. 3A, 3B, 4A, 4B and 4C are views similar to that of FIG. 2, each showing a different embodiment of the invention
  • FIG. 5 is an enlarged detailed view of the preferred embodiment of the invention.
  • FIG. 6 is a graph illustrating certain performance characteristics of the electron gun of the present invention.
  • FIG. 1 of the drawings shows a single-gun, pluralbeam color picture tube 10 which is described in detail in U. S. Pat. application Ser. No. 697,414, filed on Jan. 12, 1968, and assigned to the same assignee as this application.
  • the color picture tube 10 which is known by the name Trinitron, includes a glass envelope 11 (indicated in broken lines) having a neck 12 and cone 13 extending from the neck to a color screen S provided with the usual arrays of color phosphors S S and S and with an apertured beam-selecting grid or shadow mask 6;.
  • an electron gun A Disposed within the neck 12 is an electron gun A having cathodes K K and K each of which is a beam-generating source with its thermal electronemitting surface disposed as shown in a plane which is substantially perpendicular to the longitudinal axis of the electron gun A.
  • the beam-generating surfaces are arranged in a straight line so that the respective beams B B and B emitted therefrom are directed in substantially horizontal planes, with the alignment of the central beam B being coincident with the axis of the gun.
  • a first grid G is spaced from the beam-generating surfaces of cathodes K K and K3 and has apertures g g,,;, and g formed therein in alignment with the respective cathode beam-generating surfaces.
  • a common grid 6 is spaced from the first grid G, and has apertures g g and 3 formed therein in alignment with the respective apertures of the first grid 6,.
  • Successively arranged in the axial direction away from the common grid G are open-ended, tubular grids or electrodes G,,, G, and G respectively, with cathodes K K and K grids G, and G and electrodes 6,, G, and 0,, being maintained in the assembled positions shown in the drawings by means of suitable non-illustrated support means of an insulating material.
  • appropriate voltages are applied to the grids G, and G, and to the electrodes 6,, G. and 6,.
  • a voltage of O to minus 400V is applied to the grid G
  • a voltage of 0 to 500V is applied to the grid 6
  • a voltage of 13 to ZOKV is applied to the electrodes G and G
  • a voltage of 0 to 400V is applied to the electrode 0,, with all of these voltages being based upon the cathode voltage as a reference.
  • the voltage distributions between the respective electrodes and cathodes, and the respective lengths and diameters thereof, may be substantially identical with those of a unipotential-single beam type of electron gun which has a single cathode and first and second single-apertured grids.
  • an electron lens field will be established between grid G and the electrode G to form an auxiliary lens L as indicated in dashed lines, and an electron lens field will be established around the axis of electrode G.,, by the electrodes 6,, G, and G to form a main lens L, again as indicated in dashed lines.
  • bias voltages of V are applied to the cathodes K K and K and bias voltages of 0V, 300V, 20KV, 200V and ZOKV may be applied, respectively, to the first and second grids G, and G and the electrodes 6,, G, and G Further included in the electron gun A of FIG.
  • electron beam convergence deflecting means F which comprise shielding plates P and P disposed in the depicted spaced relationship at opposite sides of the gun axis, and axially extending deflector plates Q and O which are disposed, as shown, in outwardly-spaced, opposed relationship to shielding plates P and P, respectively.
  • the deflector plates Q and Q may, alternatively, be somewhat curved or outwardly bowed, as is well known in the art.
  • the shielding plates P and P are equally charged and disposed so that the central electron beam B will pass substantially undeflected between the shielding plates P and P, while the deflector plates Q and Q have negative charges with respect to the plates P and P so that respective electron beams B and 8,, will be convergently deflected as shown by the respective passages thereof between the plates P and Q.
  • a voltage V which is equal to the voltage applied to the electrode G may be applied to both shielding plates P and P, and a voltage V,,, which is some 200 to 300V lower than the voltage V is applied to the respective deflector plates Q and Q to result in the respective shielding plates P and P being at the same potentiai, and to result in the application of a deflecting voltage difference or convergence deflecting voltages V between the respective plates P and Q and P and Q and it is, of course, this convergence deflecting voltage V which will impart the requisite convergent deflection to the respective electron beams B and B,,.
  • the respective electron beams B B and 8, which emanate from the beam generating surfaces of the cathodes K K and K will pass through the respective grid apertures g g and g,,,, to be intensity modulated with what may be termed the red,” green and blue intensity modulation signals applied between the said cathodes and the first grid 6,.
  • the respective electron beams will then pass through the common auxiliary lens L to cross each other at the center of the main lens L. Thereafter, the central electron beam B,; will pass substantially undeflected between shielding plates P and P since the latter are at the same potential.
  • the color phosphor screen S is composed of a large plurality of sets or arrays of vertically extending red, green and blue phosphor stripes or dots S 5 and S with each of the arrays or sets of color phosphors forming a color picture element as in a chromatron type color picture tube.
  • the common spot of beam convergence corresponds to one of the thusly fonned color picture elements.
  • the voltage V may also be applied to the lens electrodes G and G and to the screen S as an anode voltage in conventional manner through a non-illustrated graphite layer which is provided on the inner surface of cone 13 of the tube envelope.
  • the grid wires of screen grid G may have a post-focusing voltage V ranging, for example, from 6 to 7KV applied thereto as indicated.
  • the respective electron beams B B and B will be converged at screen grid G and will diverge therefrom in such manner that electron beam B wll strike the blue phosphor S electron beam B will strike the green" phosphor S and electron beam B will strike the red phosphor S of the array or set corresponding to the grid aperture at which the beams converge.
  • Electron beam scanning of the face of the color phosphor screen is effected in conventional manner, for example, by horizontal and vertical deflection yoke means indicated in broken lines at D and which receives horizontal and vertical sweep signals whereby a color picture will be provided on the color screen.
  • the respective electron beams are each passed, for focusing, through the center of the main lens L of the electron gun A, the beam spots formed by impingement of the beams on the color phosphor screen 8 will be substantially free from the effects of coma and/or astigmatism of the said main lens, whereby improved color picture resolution will be provided.
  • FIG. 2 which is an enlarged view of the cathode region of the tube 10 shown in FIG. 1, shows thermal electron emitting surfaces 14, 15 and 16 of three cathodes K K and K which are arranged in a plane 21 which is perpendicular to the longitudinal axis of the tube.
  • the first grid G is arranged in a similarly perpendicular plane 22 which is located at a distance D, from the plane 21.
  • the three circular apertures g g and g,,, of grid G have equal diameters 42, and (35,
  • the second grid G is arranged in another similarly perpendicular plane 23 which is located at a distance D: from the plane 22.
  • the three apertures g g and g of grid 6, have equal diameters di da and Applicants have discovered that when a high voltage is applied to the third grid 6,, the intensity of the electric field reaching the center cathode K is greater than the intensity of the electric field reaching the other cathodes on both sides, and that the cutoff voltage (absolute value) of the cathode K is greater than the cutoff voltages of the other cathodes K and K,,. This difference in cutoff voltages causes the problems set forth hereinabove.
  • the video signal voltages applied to the cathodes K K and K may be selected to have the same voltages to produce a white picture, because of the cutoff voltage imbalance, the video signal voltages must be changed with respect to each other according to the differences in their cutoff voltages.
  • FIGS. 3A and 3B Two arrangements are shown in FIGS. 3A and 3B for providing the same cutoff characteristics for the cathodes K K and K
  • the arrangement shown in FIG. 3A the electric field reaching the cathode K through the aperture g is reduced by selecting the diameter Q5"; of the central aperture g in the first grid G, to be smaller than the diameters and da of the other apertures g and g in the first grid.
  • FIG. 3B The arrangement of FIG. 3B is like that of FIG. 3A except that the diameter d2 of the central aperture g of the second grid G, also is smaller than the diameter of its neighboring apertures.
  • FIGS. 4A, 4B and 4C Other arrangements for the same purpose are shown in FIGS. 4A, 4B and 4C.
  • the diameters of the apertures in grids G, and G are uniform, but the distances D, and/or D relating to the central electron beam (green) is made greater than the corresponding distances for the other electron beams (blue and red) in order to equalize the intensity of the electric field reaching each cathode.
  • the intensity of the electric field reaching the central cathode K is reduced by locating the beam-emitting surface 15 of that cathode farther away from grids G, and G than the other cathodes by a distance D,.
  • this has the effect of locating cathode K at a greater distance from the control electrode G,,.
  • FIG. 4B shows the same effect is achieved by bending the metal plate forming grid G, away from grid G, by a distance D, in the vicinity of the central aperture g
  • FIG. 4C shows the structural features shown in FIGS. 4A and 48 have been combined to give an even greater reduction in the electric field intensity at the surface 15 of cathode K
  • FIG. 5 shows one specific example of the gun device described in the foregoing description.
  • the material of which the grids G G and G are formed is stainless steel of 0.2 mm. thickness. Other dimensions and the voltages applied to the grids are shown in FIG. 5. It can be seen that the FIG. 3A arrangement is used in the FIG. 5 structure; that is, the diameter 4m; is 0.77 mm, and d is greater, 0.8 mm.
  • FIG. 6 shows experimentally observed relationships between various voltages observed in the structure shown in FIG. 5.
  • FIG. 6 shows experimentally observed relationships between various voltages observed in the structure shown in FIG. 5.
  • Ekco is the cutoff voltage between the cathode K and the first grid 0,; that is, the negative voltage necessary to be applied to G to cause cathode cutoff;
  • Ec is the voltage applied to the second grid G
  • the cutoff characteristics of the side beams are shown as line A in FIG. 6.
  • Line 13 represents the cutoff characteristic of a structure like the FIG. 5 structure except that both 4m; and qb are equal to 0.8 mm; that is, a structure in which the diameters of the center apertures of the first and second grids G, and G are equal to diameters of the corresponding side apertures. It is seen from FIG. 6 that there is a difference of about eight volts between the cutoff characteristic curves A and B throughout the section labeled operating range.
  • the relative reduction in the diameter of the apcrgure g and/or the aperture g (FIGS. 3A and 3B), or the increase of the distance from the beam generating surface 15 of the central cathode K to the portion of grid G having the corresponding aperture g and/or to the portion of the grid G having the corresponding aperture g serves to relatively decrease the angle of the cone that can be projected from the peripheries of the apertures to the center of the beam generating surface 15.
  • the electric field constituting the auxiliary lens L (FIG. 1) is most intense at the axis of the gun, the effect of that field at surface 15 of central cathode K is minimized so as to be equalized with the effect of the field at surfaces 14 and 16 of side cathodes KB and KB.
  • An electron gun device for a color picture tube comprising two side cathodes and a central cathode therebetween having beam generating surfaces arranged substantially in a row for emitting electrons generally in parallel directions, first and second grids spaced successively in the axial direction away from said beam generating surfaces and having apertures respectively aligned with the beam generating surfaces and through which the emitted electrons are collimated into respective electron beams, and a plurality of electrodes maintained at different potentials and arranged axially following said second grid to provide an electric field defining a main lens means by which said beams are focused and cooperating with said second grid to provide another electric field defining an auxiliary lens means by which the beams from said side cathodes are converged with respect to the beam from said central cathode for passage of all of the beams through the center of said main lens means, the angle of a cone that can be projected to the center of said beam generating surface of said central cathode from the peripheries of the respective aligned apertures of said grids
  • An electron gun in which said beam generating surface of the central cathode is at a distance from the aligned aperture in at least one of said first and second grids that is greater than the dis: tance from the beam generating surfaces of said side cathodes to the corresponding apertures of the grids.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Nanotechnology (AREA)
  • Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Theoretical Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)
US00815941A 1968-04-14 1969-04-14 Electron gun device for color tube Expired - Lifetime US3755703A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2459068A JPS512787B1 (enrdf_load_stackoverflow) 1968-04-14 1968-04-14
JP2458968A JPS512789B1 (enrdf_load_stackoverflow) 1968-04-14 1968-04-14

Publications (1)

Publication Number Publication Date
US3755703A true US3755703A (en) 1973-08-28

Family

ID=26362137

Family Applications (1)

Application Number Title Priority Date Filing Date
US00815941A Expired - Lifetime US3755703A (en) 1968-04-14 1969-04-14 Electron gun device for color tube

Country Status (3)

Country Link
US (1) US3755703A (enrdf_load_stackoverflow)
FR (1) FR2006213A1 (enrdf_load_stackoverflow)
NL (1) NL161916C (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3883771A (en) * 1969-03-07 1975-05-13 Akio Ohgoshi Collinear electron gun system including accelerating grid having greater effective thickness for off axis beams
US4028581A (en) * 1976-06-24 1977-06-07 Gte Sylvania Incorporated Plural beam electron gun assembly
US4029988A (en) * 1976-06-24 1977-06-14 Gte Sylvania Incorporated CRT in-line electron gun assembly
US4061941A (en) * 1976-06-24 1977-12-06 Gte Sylvania Incorporated CRT electron gun assembly
US4119883A (en) * 1969-06-30 1978-10-10 Sony Corporation Cathode ray tube
US4181870A (en) * 1978-03-08 1980-01-01 Zenith Radio Corporation Assembly of electron guns having different gamma values
US4514659A (en) * 1982-03-04 1985-04-30 Rca Corporation Inline electron gun for high resolution color display tube

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS598246A (ja) * 1982-07-05 1984-01-17 Toshiba Corp 電子銃
FR3111308B1 (fr) 2020-06-15 2025-01-10 Psa Automobiles Sa Procédé et dispositif de réglage de fonctions de confort et/ou de sécurité d’un véhicule

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2726347A (en) * 1953-04-30 1955-12-06 Rca Corp Multiple-beam electron gun
US2735031A (en) * 1951-02-15 1956-02-14 woodbridge
US2825847A (en) * 1955-05-12 1958-03-04 Philips Corp Cathode-ray tube for the reproduction of colour television images
US2825845A (en) * 1954-04-03 1958-03-04 Philips Corp Cathode ray tube for reproducing color television images
US2850658A (en) * 1956-02-21 1958-09-02 Rca Corp Non-symmetrical cathodes in cathode ray tubes
US2861208A (en) * 1955-03-01 1958-11-18 Rca Corp Combination focusing and converging lens for multiple beam tubes
US2887598A (en) * 1956-04-16 1959-05-19 Rca Corp Plural gun cathode ray tube
US2957106A (en) * 1954-08-12 1960-10-18 Rca Corp Plural beam gun
US3294999A (en) * 1962-08-06 1966-12-27 Rca Corp Cathode ray tube
US3448316A (en) * 1967-01-14 1969-06-03 Sony Corp Cathode ray tube

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2735031A (en) * 1951-02-15 1956-02-14 woodbridge
US2726347A (en) * 1953-04-30 1955-12-06 Rca Corp Multiple-beam electron gun
US2825845A (en) * 1954-04-03 1958-03-04 Philips Corp Cathode ray tube for reproducing color television images
US2957106A (en) * 1954-08-12 1960-10-18 Rca Corp Plural beam gun
US2861208A (en) * 1955-03-01 1958-11-18 Rca Corp Combination focusing and converging lens for multiple beam tubes
US2825847A (en) * 1955-05-12 1958-03-04 Philips Corp Cathode-ray tube for the reproduction of colour television images
US2850658A (en) * 1956-02-21 1958-09-02 Rca Corp Non-symmetrical cathodes in cathode ray tubes
US2887598A (en) * 1956-04-16 1959-05-19 Rca Corp Plural gun cathode ray tube
US3294999A (en) * 1962-08-06 1966-12-27 Rca Corp Cathode ray tube
US3448316A (en) * 1967-01-14 1969-06-03 Sony Corp Cathode ray tube

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3883771A (en) * 1969-03-07 1975-05-13 Akio Ohgoshi Collinear electron gun system including accelerating grid having greater effective thickness for off axis beams
US4119883A (en) * 1969-06-30 1978-10-10 Sony Corporation Cathode ray tube
US4028581A (en) * 1976-06-24 1977-06-07 Gte Sylvania Incorporated Plural beam electron gun assembly
US4029988A (en) * 1976-06-24 1977-06-14 Gte Sylvania Incorporated CRT in-line electron gun assembly
US4061941A (en) * 1976-06-24 1977-12-06 Gte Sylvania Incorporated CRT electron gun assembly
US4181870A (en) * 1978-03-08 1980-01-01 Zenith Radio Corporation Assembly of electron guns having different gamma values
US4514659A (en) * 1982-03-04 1985-04-30 Rca Corporation Inline electron gun for high resolution color display tube

Also Published As

Publication number Publication date
NL161916C (nl) 1980-03-17
DE1918912A1 (de) 1969-11-06
DE1918912B2 (de) 1972-08-24
FR2006213A1 (enrdf_load_stackoverflow) 1969-12-19
NL6905721A (enrdf_load_stackoverflow) 1969-10-16
NL161916B (nl) 1979-10-15

Similar Documents

Publication Publication Date Title
GB2086649A (en) Colour picture tube having an inline electron gun
US3949262A (en) Cathode ray tube with compensation for beam landing spot distortion due to wide-angle beam deflection
US4528476A (en) Cathode-ray tube having electron gun with three focus lenses
US5412277A (en) Dynamic off-axis defocusing correction for deflection lens CRT
US3970890A (en) Plural beam cathode ray tube including an astigmatic electron lens and self-converging
US3755703A (en) Electron gun device for color tube
US3651359A (en) Abberation correction of plurality of beams in color cathode ray tube
US3678320A (en) Cathode ray tube having triangular gun array and curvilinear spacing between the fourth and fifth grids
US3524094A (en) Wide deflection angle cathode-ray tube with a lens for focussing the electron-beam at an elongate spot on a screen and an astigmatic correcting lens
US3696261A (en) Cathode ray tube with plural beams for each color element
US3619686A (en) Color cathode-ray tube with in-line plural electron sources and central section of common grid protruding toward central source
US3028521A (en) Image-reproducting device
US2806163A (en) Triple gun for color television
US2726348A (en) Multiple beam gun
US3639796A (en) Color convergence system having elongated magnets perpendicular to plane of plural beams
EP0452789B1 (en) Color picture tube having inline electron gun with focus adjustment means
US3883771A (en) Collinear electron gun system including accelerating grid having greater effective thickness for off axis beams
US3778666A (en) Convergence deflecting device for single-gun, plural-beam color picture tube
US3579008A (en) Color tube having asymetrical electrostatic convergence correction system
US3571643A (en) Plural beam electron gun for a color picture tube with different-sized control grid apertures
US3678329A (en) Cathode ray tube
US4620134A (en) Cathode-ray tube
US2747134A (en) Dual focus cathode-ray tubes
US3732457A (en) Electrode lens potential arrangement for a post-acceleration picture tube
US3651369A (en) Cathode ray tube