EP0283190A2 - Elektronenkanone für Farbbildröhre - Google Patents

Elektronenkanone für Farbbildröhre Download PDF

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Publication number
EP0283190A2
EP0283190A2 EP88301995A EP88301995A EP0283190A2 EP 0283190 A2 EP0283190 A2 EP 0283190A2 EP 88301995 A EP88301995 A EP 88301995A EP 88301995 A EP88301995 A EP 88301995A EP 0283190 A2 EP0283190 A2 EP 0283190A2
Authority
EP
European Patent Office
Prior art keywords
electrode
grid
electron gun
color picture
picture tube
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.)
Ceased
Application number
EP88301995A
Other languages
English (en)
French (fr)
Other versions
EP0283190A3 (de
Inventor
Hidemasa Komoro
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.)
Hitachi Ltd
Original Assignee
Hitachi 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 Hitachi Ltd filed Critical Hitachi Ltd
Publication of EP0283190A2 publication Critical patent/EP0283190A2/de
Publication of EP0283190A3 publication Critical patent/EP0283190A3/de
Ceased 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
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • 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
    • 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

Definitions

  • the present invention relates to an in-line type electron gun for a color picture tube, and more particularly to the electrode structure of an electrode for forming an electron lens, well suited to enhance focusing characteristics.
  • the diameter of a main lens becomes smaller than in a delta arrayal type electron gun. While the diameter of the neck of a glass bulb is better as it is smaller in view of the restrictions of deflecting current power, convergence, etc., the diameter of the main lens becomes still smaller to degrade focusing characteristics.
  • the gap between the outside diameter of the electron gun and the inside diameter of the neck needs to be set at or above 1 mm by way of example in order to lessen the influences of undesirable electron emission etc. There are such numerous restrictions due to which the diameter of the main lens cannot be enlarged. Accordingly, a multistage focusing type electron gun has been proposed as an expedient for attaining a good focusing performance among the numerous restrictions.
  • the multistage focusing type electron gun can focus electron beams gently, and can improve the spherical aberrations of electron lenses.
  • Fig. 4 is a partly sectional side view of a typical electron gun of the multistage focusing type.
  • the electron gun is constructed of a cathode 1, a first grid 2, a second grid 3, a third grid 4, a fourth grid 5, a fifth grid 6 and a sixth grid 7.
  • a lens system which contributes to direct electron beams in parallel to each other toward a phosphor screen is formed by the third grid 4, fourth grid 5 and fifth grid 6, while another lens system which contributes to focus the parallel beams on the phosphor screen (although actual focusing points lie on a shadow mask, they shall hereinafter be expressed as lying on the phosphor screen for the sake of brevity) is formed by the fifth grid 6 and sixth grid 7.
  • a main lens includes these lens systems.
  • the third grid 4 and fifth grid 6 are electrically connected and have a focusing voltage of, for example, about 7 kV applied thereto, while the fourth grid 5 and sixth grid 7 are electrically connected and have an anode voltage of, for example, about 25 kV applied thereto.
  • the whole electron gun has the focusing characteristics improved sharply as the multistage focusing type electron gun which has both a bipotential type and a unipotential type.
  • numeral 8 indicates multiform glass.
  • the multistage focusing type electron gun of the above-stated construction attains satisfactory focusing characteristics in practical use.
  • the distance between an electron gun and a phosphor screen differs from that of the conventional tube, and hence, the fifth grid 6 and the sixth grid 7 in which the end faces 6 ⁇ and 7 ⁇ of respective cylinder portions formed on both the sides thereof have unequal inclinations need to be prepared every size.
  • An object of the present invention is to eliminate the difficulty of the prior art mentioned above, and to provide an electron gun for a color picture tube according to which a desired converging angle is attained using also existing cylinder portions with their end faces inclined, and focusing characteristics can be enhanced for various kinds of products.
  • the electron gun for a color picture tube consists in that an electric field correcting electrode is disposed in at least one existing grid electrode having a cylinder portion one end face of which is inclined.
  • the electric field correcting electrode is provided as stated above, whereby electron beams move substantially in parallel, and a converging angle is properly controlled.
  • the electron gun to which the present invention is applicable has the grid electrode in which the end face of the cylinder portion is inclined. Accordingly, the electron gun to which the present invention is applicable comprises first electrode means to direct at least two electron beams toward a phosphor screen and along initial paths parallel to each other, and second electrode means to establish substantially separate main lenses for the paths of the respective electron beams, thereby to focus the electron beams on a predetermined position on a predetermined surface, for example, the phosphor screen. To this end, grid electrodes which have apertures coaxial with the electron beam paths are opposingly arranged.
  • the electric field correcting electrode disposed anew in the electron gun of the present invention is opposingly arranged at a predetermined interval from the cylinder portion.
  • it is often arranged on the inclined end face side of the cylinder portion. It is usually convenient that the electric field correcting electrode is flattened and is caused to intersect orthogonally to the center axis, but this setup is not restrictive.
  • the distance l1 or l2 between the electric field correcting electrode and the cylinder portion of the grid electrode may be experimentally or calculatively determined so that the distance X between the focusing point of the rectilinearly-propagating electron beam (ordinarily, the central electron beam) on the predetermined surface and the focusing point of the deflected electron beam (ordinarily, the outer electron beam) on the same surface may become a desired value, for example, within 1 mm.
  • An appropriate plus voltage is applied to the electric field correcting electrode, and it is usually convenient to electrically connect the correcting electrode with the corresponding grid electrode. Needless to say, the electric field correcting electrode is also formed with apertures for the respective electron beams.
  • Fig. 1 is a sectional view of essential portions which shows an embodiment of an electron gun for a color picture tube according to the present invention, and in which identical symbols are assigned to the same portions as in the figure referred to before.
  • an electric field correcting electrode 6A which includes respective electron beam apertures 6A s1 , 6A s2 and 6A c coaxial with cylinder portions 6 s1 , 6 s2 on both outer sides having inclined end faces and with a central cylinder portion 6 c is arranged in opposition to the cylinder portions.
  • an electric field correcting electrode 7A which includes respective electron beam apertures 7A s1 , 7A s2 and 7A c coaxial with cylinder portions 7 s1 , 7 s2 on both outer sides having inclined end faces and with a central cylinder portion 7 c is arranged in opposition to the cylinder portions.
  • the center axes of the respective electron beam apertures were held in agreement with those of the corresponding cylinder portions.
  • the diameter of each aperture was 5.5 mm equal to the inside diameter of the corresponding cylinder portion.
  • the distances Y between the center axis S of the central cylinder portion 6 c (or 7 c ) and the center axes of the sideward cylinder portions 6 s1 , 6 s2 (or 7 s1 , 7 s2 ) were set at 6.6 mm.
  • lengths n1 and n2 in Fig. 1 were respectively set at 3.1 mm and 2.8 mm.
  • the electric field correcting electrode 6A (or 7A) which is flat is provided near the axial central part of the grid electrode 6 (or 7), but this setup is not restrictive. Further, a conventional electrode material for picture tubes may be employed as the material of the electric field correcting electrode, and the use of the same material as that of the grid electrode is convenient.
  • electron lenses based on electric fields are respectively formed between "the cylinder portions 6 s1 , 6 s2 of the fifth grid electrode 6 located on both the sides and having the inclined end faces and the central cylinder portion 6 c thereof" and "the corresponding electron beam apertures 6A s1 , 6A s2 and 6A c of the electric field correcting electrode 6A". Therefore, the apparent inclination of an electron lens formed by the fifth grid electrode 6 only is corrected by the above electron lenses, so that the converging angles of the electron beams are corrected and controlled.
  • the electric field correcting electrode 7A also for the sixth grid electrode 7, the apparent inclination of an electron lens is corrected similarly to the above.
  • the distance X which the electron beams are converged in the direction of the center axis S is substantially in a rectilinear relation with the value of the distance l1 or l2 as shown in Fig.
  • Fig. 5 shows the whole configuration of an example of the electron gun for the color picture tube in the present embodiment.
  • an electron gun 10 is so constructed that a cathode K, a first grid G1, a second grid G2, a third grid G3, a fourth grid G4, a fifth grid G5, a sixth grid G6 and a shielding cup 12 with predetermined dimensions are successively stacked on stem glass 11b planted with stem pins 11a and are supported and fixed by multiform glass 10a.
  • the fourth grid G4 (5) and the six grid G6 (7) are electrically connected, and an anode voltage of 25 kV is applied thereto.
  • the third grid G3 (4) and the fifth grid G5 (6) are electrically connected, and a focusing voltage having a magnitude of 33 % of the anode voltage is applied thereto.
  • the flat outer contour of the electric field correcting electrode 6A or 7A in the present embodiment is substantially the same as the contour of a grid section cut by the plane of the correcting electrode in the insertion part thereof.
  • the present invention is not restricted to this case, but the electric field correcting electrode may be provided in at least the fifth grid electrode 6. More specifically, in a case where the correcting electrode is provided in the sixth grid electrode 7, a wide control of converging angle is impossible because the shielding cup is disposed at the front end part of this sixth grid electrode, namely, on the phosphor screen side.
  • the converging angle can be widely controlled, and the greater part of the converging angle can be determined.
  • the correcting electrode is also provided in the sixth grid electrode 7, it becomes possible to finely adjust the converging angle and to set an electron beam converging angle as desired. However, even in the case where the electric field correcting electrode is disposed in only the sixth grid electrode 7, an effect to that extent is produced.
  • the present invention is not restricted thereto. It is needless to say that effects similar to the foregoing are attained even when the correcting electrode is constructed of a cup-shaped electrode having a cylinder portion.
  • the electron gun of the present invention may employ the structure of the prior-art electron gun having the cylinder portion in which the end face at one end is inclined, except that the electric field correcting electrode or electrodes is/are disposed in the fifth grid or in both the fifth and sixth grids.
  • an electric field correcting electrode is disposed in an existing grid electrode having a cylinder portion whose end face is inclined, whereby the converging angle of an electron beam can be controlled. Therefore, when combined with various existing grid electrodes having typical dimensions of the greatest converging forces, the invention brings forth such very excellent effects that focusing characteristics can be enhanced and that electrodes can be made common for color picture tubes of various sizes.

Landscapes

  • Electrodes For Cathode-Ray Tubes (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)
  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
EP88301995A 1987-03-20 1988-03-08 Elektronenkanone für Farbbildröhre Ceased EP0283190A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP63788/87 1987-03-20
JP62063788A JPS63231845A (ja) 1987-03-20 1987-03-20 カラ−ブラウン管用電子銃

Publications (2)

Publication Number Publication Date
EP0283190A2 true EP0283190A2 (de) 1988-09-21
EP0283190A3 EP0283190A3 (de) 1989-07-12

Family

ID=13239463

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88301995A Ceased EP0283190A3 (de) 1987-03-20 1988-03-08 Elektronenkanone für Farbbildröhre

Country Status (4)

Country Link
EP (1) EP0283190A3 (de)
JP (1) JPS63231845A (de)
KR (1) KR910001870B1 (de)
CN (1) CN1008312B (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100504527B1 (ko) * 1998-11-18 2005-09-26 엘지전자 주식회사 칼라 음극선관용 전자총

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3011090A (en) * 1952-06-24 1961-11-28 Rca Corp Plural beam tube
JPS5763750A (en) * 1980-10-03 1982-04-17 Hitachi Ltd Control picture tube electron gun

Also Published As

Publication number Publication date
JPS63231845A (ja) 1988-09-27
CN1008312B (zh) 1990-06-06
CN88101547A (zh) 1988-09-28
KR880011862A (ko) 1988-10-31
EP0283190A3 (de) 1989-07-12
KR910001870B1 (ko) 1991-03-28

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