US3898521A - Electron beam control system - Google Patents

Electron beam control system Download PDF

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Publication number
US3898521A
US3898521A US436792A US43679274A US3898521A US 3898521 A US3898521 A US 3898521A US 436792 A US436792 A US 436792A US 43679274 A US43679274 A US 43679274A US 3898521 A US3898521 A US 3898521A
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United States
Prior art keywords
electron beams
electron
magnetic field
dynamic convergence
control system
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
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US436792A
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English (en)
Inventor
Tsunenari Saito
Yoshio Aoki
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Sony Corp
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Sony Corp
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Publication date
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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
    • H01J29/70—Arrangements for deflecting ray or beam
    • H01J29/701—Systems for correcting deviation or convergence of a plurality of beams by means of magnetic fields at least
    • H01J29/702—Convergence correction arrangements therefor
    • H01J29/705—Dynamic convergence systems
    • 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
    • H01J29/51—Arrangements for controlling convergence of a plurality of beams by means of electric field only
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/16—Picture reproducers using cathode ray tubes
    • H04N9/28—Arrangements for convergence or focusing
    • H04N9/285—Arrangements for convergence or focusing using quadrupole lenses
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/56—Correction of beam optics
    • H01J2229/568—Correction of beam optics using supplementary correction devices
    • H01J2229/5681—Correction of beam optics using supplementary correction devices magnetic
    • H01J2229/5687—Auxiliary coils

Definitions

  • This invention relates generally to an electron beam control system for use with a cathode ray tube, and more particularly to an electron beam shape control system for use with in-line type color cathode ray tube for dynamic correction of beam shape deformation.
  • a dynamic convergence device is necessary for a color cathode ray tube.
  • a magnetic type dynamic convergence device is used for converging three electron beams on the screen of the cathode ray tube.
  • the shape of the electron beams is deformed by a magnetic field of the magnetic type convergence device, and hence the resolution of a reproduced picture on the screen of the cath ode ray tube is aggravated.
  • This invention provides an electron beam control system for use with an in-line type color cathode ray tube for dynamic correction or compensation of electron beam shape deformation.
  • a color cathode ray tube with the electron beam control system of this invention has a dynamic convergence device composed of a pair of two-pole magnetic yokes aligned in horizontal and a beam shape correction or compensation coil composed of a pair of two pole magnetic yokes aligned in vertical.
  • a parabolic signal is supplied to the dynamic convergence coil and the beam shape correction coil commonly to produce magnetic fields contrary in pole with each other, thereby correcting or compensating for a deformation of the electron beam shape caused by a magnetic field of the dynamic convergence coil.
  • FIG. I shows a plane sectional view of an in-line type color cathode ray tube of the prior art
  • FIG. 2 shows a sectional view taken on the line aa in FIG. I;
  • FIG. 3 shows a waveform chart of a dynamic conver gence current used for the cathode ray tube of FIG. 1;
  • FIG. 4 shows a cross section of an electron beam when no dynamic convergence current flows in a dynamic convergence coil of the cathode ray tube of FIG. 1;
  • FIG. 5 shows a cross section of an electron beam when the dynamic convergence current flows in the dynamic convergence coil of cathode ray tube of FIG. 1'
  • FIG. 6 is a graphic diagram showing the relationship between the dynamic convergence current and a beam spot size of the electron beam. and between a correction current and a beam spot size of the electron beam, respectively;
  • FIG. 7 shows a plane sectional view of an in-line type color cathode ray tube with the electron beam control system according to this invention.
  • FIG. 8 shows a sectional view taken on the line b-b in FIG. 7.
  • FIG. 1 shows an embodiment of the in-line type color cathode ray tube of the prior art.
  • red, green and blue cathodes K K and K are arranged sequentially to be aligned substantially in a common horizontal plane and first to fifth grids G to G are coaxially and sequentially arranged common to the cathodes K K and K Red, green and blue electron beams R, G and B emitted from the cathodes K K and K are prefocused by a subsidiary electron lens L formed by the second and third grids G and G to cross over at the center of a main electron lens L formed by the third to fifth grids G to G substantially and thereafter to diverge.
  • a static convergence device or means I which consists of a pair of inner convergence plates 2 and 3 and a pair of outer convergence plates 4 and 5.
  • the inner convergence plates 2 and 3 are supplied with an anode voltage E while the outer convergence plates 4 and 5 are supplied with a convergence voltage E which is lower than the anode voltage E, by several hundred volts to perform the static convergence operation.
  • a dynamic convergence yoke 6 At the position where the static convergence device 1 is provided in the neck portion of the cathode ray tube, there is provided a dynamic convergence yoke 6 outside the neck portion.
  • reference numeral 7 indicates a horizontal and vertical deflection device.
  • the dynamic convergence yoke 6 consists of, for example, a pair of two-pole electromagnetic elements which include U-shaped cores 8 and 9, and coils l0 and II which are wound on the cores 8 and 9, respectively.
  • the coils l0 and 11 are aligned in the horizontal plane around the neck portion of the cathode ray tube.
  • the parabolic signal i shown in FIG. 3 is supplied to flow through the coils l0 and 11, the dynamic convergence yoke 6 produces a four pole magnetic field as shown in FIG. 2 for moving side electron beams of three electron beams in the opposite directions in the horizontal plane.
  • each beam spot shape of the three electron beams on the screen becomes to a circular one as shown in FIG. 4 which is minimum in cross section area or size. (In FIG. 4, only one of the three beam spots is shown.)
  • a magnetic field H in the vertical direction is produced and a magnetic field H in the horizontal direction is also produced.
  • a force F which acts on the respective beams for stretching the same in the horizontal
  • a force F which acts on the respective beams for pressing the same in the vertical direction
  • FIG. 2 which is viewed from the cathodes, and consequently each beam spot shape of the three electron beams on the screen is deformed in a diamond shape as shown in FIG. 5 and increases in cross-sectional area or beam spot size.
  • FIG. 5 shows only one deformed beam spot, it is appreciated that the other two beam spots (not shown) are similarly deformed. Accordingly, a reproduced picture is deteriorated in resolution.
  • FIG. 6 shows a graph of the relationship between the dynamic convergence current and the beam spot size on the screen and between a correction current and the beam spot size, respectively, in which the ordinate represents the beam spot size m (where 0 indicates the horizontal size of the beam spot and b the vertical size of the beam spot) and the abscissa the dynamic convergence and correction currents I in mA.
  • a curve 12 shows the beam spot size variation in response to the variation of the dynamic convergence current I flowing through the dynamic convergence yoke 6.
  • FIG. 7 illustrates a color cathode ray tube employing the electron beam control system of this invention and hence in which reference numerals and symbols same as those used in FIGS. 1 and 2 designate the same elements.
  • a correction or compensation yoke 13 which may produce a magnetic field opposite in polarity with respect to the magnetic field produced by the dynamic convergence yoke 6, is provided outside the neck portion of the cathode ray tube and in the vicinity of the main electron lens L in the tube axis.
  • the correction yoke 13 can be a pair of two-pole electro-magnetic ele ment similar to the dynamic convergence yoke 6.
  • cores l4 and 15 which are substantially same as the cores 8 and 9 of dynamic convergence yoke 6 in shape, are disposed around the neck portion in the vicinity of the main electron lens L such that the cores 14 and 15 are opposed to each other with gripping the neck portion therebetween in the vertical direction.
  • coils l6 and 17 are wound on the cores l4 and 15, re spectively, same in number as the coils l0 and 11 of yoke 6.
  • the coils l0 and ll of the yoke 6 and the coils l6 and 17 of the yoke 13 are connected in series, as shown in FIG. 8, and a dynamic convergence voltage e is impressed across the both ends of series connected coils to produce correction or com pensation magnetic fields H and H in the horizontal and vertical directions which are opposite in direction to the fields H, and H produced by the yoke 6.
  • the correction yoke 13 is provided in the vicinity of the main electron lens L where the three electron beams cross-over, the correction magnetic field acts on the three electron beams equally and the correction yoke 13 does not affect the dynamic convergence operation caused by the dynamic convergence yoke 6 or the predetermined dynamic convergence operation is achieved as it is.
  • An electron beam control system for apparatus utilizing a color cathode ray tube comprising:
  • a color cathode ray tube having a luminescent screen, beam generating means for emitting a plurality of electron beams to said screen, all of said electron beams being aligned substantially in a common plane, and an electron focus lens disposed between said beam generating means and said screen having a substantially central portion at which said electron beams cross over;
  • beam deflecting means disposed between said beam generating means and said screen, said beam deflecting means producing a magnetic field through which said electron beams pass for moving said electron beams in a direction parallel to said common plane, said magnetic field affecting deformation of the cross-sectional shape of each of said electron beams;
  • means for compensating for the cross-sectional shape deformation of each of the electron beams including a magnetic yoke disposed around the substantially central portion of said electron focus lens, said magnetic yoke producing an additional magnetic field through which each of said electron beams pass for acting on the cross-sectional shape of each of said electron beams so as to compensate for the deformation caused by the magnetic field of said beam deflecting means.
  • said beam deflecting means comprises with respect to the magnetic field produced by said dynamic convergence means to thereby exert a force on each of said electron beams that is opposite to the force exerted thereon by the magnetic field produced by said dynamic convergence means.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)
US436792A 1973-02-02 1974-01-25 Electron beam control system Expired - Lifetime US3898521A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1973014681U JPS5646297Y2 (de) 1973-02-02 1973-02-02

Publications (1)

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US3898521A true US3898521A (en) 1975-08-05

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Application Number Title Priority Date Filing Date
US436792A Expired - Lifetime US3898521A (en) 1973-02-02 1974-01-25 Electron beam control system

Country Status (8)

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US (1) US3898521A (de)
JP (1) JPS5646297Y2 (de)
CA (1) CA995727A (de)
DE (1) DE2404942C3 (de)
FR (1) FR2216669B1 (de)
GB (1) GB1442723A (de)
IT (1) IT1006240B (de)
NL (1) NL184988C (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4528476A (en) * 1983-10-24 1985-07-09 Rca Corporation Cathode-ray tube having electron gun with three focus lenses
US4737682A (en) * 1987-07-20 1988-04-12 Rca Corporation Color picture tube having an inline electron gun with an einzel lens
US4742266A (en) * 1987-07-20 1988-05-03 Rca Corporation Color picture tube having an inline electron gun with an einzel lens
US4745331A (en) * 1987-07-20 1988-05-17 Rca Licensing Corporation Color picture tube having an inline electron gun with an einzel lens
GB2202082A (en) * 1986-12-27 1988-09-14 Sony Corp Cathode ray tubes
US6703801B2 (en) * 2000-12-06 2004-03-09 Matsushita Electric Industrial Co., Ltd. Deflection yoke and color cathode ray tube device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5227216A (en) * 1975-08-25 1977-03-01 Sony Corp Convergence corrector of color cathode ray tube

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3462638A (en) * 1967-07-10 1969-08-19 Sony Corp Electron beam correction apparatus for color picture tube
US3735189A (en) * 1971-03-19 1973-05-22 Zenith Radio Corp Blue droop correction circuit with a single supplemental correction coil

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3462638A (en) * 1967-07-10 1969-08-19 Sony Corp Electron beam correction apparatus for color picture tube
US3735189A (en) * 1971-03-19 1973-05-22 Zenith Radio Corp Blue droop correction circuit with a single supplemental correction coil

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4528476A (en) * 1983-10-24 1985-07-09 Rca Corporation Cathode-ray tube having electron gun with three focus lenses
GB2202082A (en) * 1986-12-27 1988-09-14 Sony Corp Cathode ray tubes
US4857796A (en) * 1986-12-27 1989-08-15 Sony Corporation Cathode-ray tube with electrostatic convergence means and magnetic misconvergence correcting mechanism
GB2202082B (en) * 1986-12-27 1990-09-19 Sony Corp Cathode ray tubes
US4737682A (en) * 1987-07-20 1988-04-12 Rca Corporation Color picture tube having an inline electron gun with an einzel lens
US4742266A (en) * 1987-07-20 1988-05-03 Rca Corporation Color picture tube having an inline electron gun with an einzel lens
US4745331A (en) * 1987-07-20 1988-05-17 Rca Licensing Corporation Color picture tube having an inline electron gun with an einzel lens
US6703801B2 (en) * 2000-12-06 2004-03-09 Matsushita Electric Industrial Co., Ltd. Deflection yoke and color cathode ray tube device

Also Published As

Publication number Publication date
DE2404942A1 (de) 1974-08-08
GB1442723A (en) 1976-07-14
NL7401532A (de) 1974-08-06
NL184988B (nl) 1989-07-17
CA995727A (en) 1976-08-24
JPS5646297Y2 (de) 1981-10-29
FR2216669B1 (de) 1978-06-16
IT1006240B (it) 1976-09-30
DE2404942C3 (de) 1978-07-06
FR2216669A1 (de) 1974-08-30
NL184988C (nl) 1989-12-18
DE2404942B2 (de) 1977-11-24
JPS49116065U (de) 1974-10-03

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