US3831051A - Color picture tube with deflection center control - Google Patents

Color picture tube with deflection center control Download PDF

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Publication number
US3831051A
US3831051A US00862411A US86241169A US3831051A US 3831051 A US3831051 A US 3831051A US 00862411 A US00862411 A US 00862411A US 86241169 A US86241169 A US 86241169A US 3831051 A US3831051 A US 3831051A
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United States
Prior art keywords
magnetic
picture tube
color picture
flux
envelope
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Expired - Lifetime
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US00862411A
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English (en)
Inventor
A Ohgoshi
Y Katagiri
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Sony Corp
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Sony Corp
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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
    • 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
    • H01J29/006—Arrangements for eliminating unwanted temperature effects

Definitions

  • ABSTRACT A color picture tube consisting of a shadow mask, color prosphors, a deflection yoke and a magnetic compensating alloy ring provided adjacent to the deflection yoke for changing a magnetic flux therethrough in response to the temperature on the shadow mask.
  • This invention relates to a color picture tube, and more particularly to a system of compensation for mislanding of an electron beam resulting from the temperature variation in the color picture tube.
  • a color picture tube has incorporated in its envelope the so-called shadow mask or a grid apparatus made up of many metal strips so as to ensure impingement of a plurality of electron beams on predetermined color phosphors.
  • the shadow mask or the grid apparatus is subjected to thermal expansion to be deformed.
  • SUMMARY OF THE INVENTION netic member is formed of an iron-nickel, nickelcopper alloy or the like which has negative magnetictemperature characteristics and is commonly-referred to as a magnetic compensating alloy. According to our experiments, it has been found that the rate of temperature rise to time at the shadow mask or grid apparatus is substantially the same as those at the funnel and neck portions of the color picture tube and at a position where the deflection yoke is disposed. Consequently, the aforementioned magnetic compen sating alloy member need not always be located in the proximity of the shadow mask or the grid apparatus and the provision of such an alloy member at the abovementioned place enables the compensation of mislanding of electron beams. 1
  • one object of this invention is to provide a color picture tube which is adapted to compensate for mislanding of electron beams without the use of mechanical means.
  • Another object of this invention is to provide a color picture tube which is designed to move the deflection center in accordance with the degree of mislanding of electron beams resulting from thermal expansion of a shadow mask.
  • Still another object of this invention is to provide a color picture tube in which the magnetic flux distribution over the deflection yoke is caused to vary with temperature by the use of a magnetic compensating alloy member so as to avoid color contamination due to mislanding of electron beams.
  • FIG. 1 is a cross-sectional view schematically illustrating a color picture tube for explaining the present invention
  • FIG. 2 is a cross-sectional view of the principal portion of a color picture tube, illustrating one example of this invention
  • FIG. 3 is a graph showing the temperature-permeability characteristic of a magnetic compensating alloy usable in this invention.
  • FIGS. 4A, 4B and 5A, 5B are respectively schematic plan and cross-sectional views for explaining the operational principles of this invention.
  • FIGS. 6A and 6B are respectively plan and crosssectional views of the principal portion of a color picture tube, illustrating another example of this invention.
  • FIG. 7A is a perspective view showing one example of a ring-shaped magnetic compensating alloy member that may be used in accordance with the invention
  • FIG. 7B is a similar view showing the ring-shaped magnetic compensating alloy member employed in the color picture tube of FIGS. 6A and 6B;
  • FIG. 8 is a schematic perspective view of another example of the ring-shaped magnetic compensating alloy member as applied to an electron gun device.
  • FIG. 1 is a schematic cross-sectional view of a color picture tube, for explaining mislanding of an electron beam which is caused by deformation of a mask due to interior surface of a color picture tube 1, is heated by the impingement of an'electron beam to be thermally expanded as indicated by 3' (shown on the inside of the normal position for convenience of illustration), the deformation of the mask 3 causes displacement of the apertures 4 of the mask as indicated by 4 to introduce mislanding of the electron beam.
  • This displacement of the apertures 4 becomes greater as the periphery of the mask 3 is approached from the center thereof. For example, the central point of an aperture 3a shifts from A to A' as shown.
  • a mechanical movement of the mask necessitates the use of a complicated support for supporting the mask to the panel portion at a predetermined position and is likely to introduce uncertainty in the supporting of the mask, so that the shock resistance of the mask is not great when subjected to shock conditions.
  • the incident angle of the beam to an aperture 3a is smaller than that obtainable with the deflection center 0 at its initial position. Accordingly, even if the electron beam deflection center 0 is shifted rearwardly on the line X-X to a position O" spaced from its initial position by a predetermined distance L, the electron beam passing through the aperture 3a' is impinged upon the phosphor screen 2 at the normal position P. Thus, the mislanding of the electron beam can be compensated for.
  • the present invention is to detect a temperature change of a portion at which temperature varies in substantially the same manner as that of the mask and to locate the deflection center of the deflection yoke in accordance with the detected temperature change so as to avoid the mislanding of the electron beam.
  • the compensation of the mislanding is required for both horizontal and vertical deflections but in the case of using a mask such as a grid apparatus having slits the compensation is necessary only for horizontal deflection.
  • FIG. 2 one concrete embodiment of this invention will hereinbelow be described in detail, in which similar elements to those in FIG. 1 are identified by the similar reference numerals and will not be described for the sake of brevity.
  • the temperature rise at the funnel and neck of the picture tube and the portion where the deflection center is located is substantially equal to that of the mask.
  • a ring-shaped magnetic compensating alloy member 7 of a high negative temperature coefficient to magnetism that is, the permeability of which member appreciably decreases with an increase in temperature.
  • the ring-shaped magnetic compensating alloy member 7 may be formed of an alloy composed of, for example, 70 percent of iron and 30 percent of nickel, and one example of its temperature-permeability characteristic is as shown in FIG. 3 in which the abscissa represents temperature and the ordinate permeability.
  • the permeability of the ringshaped magnetic compensating alloy member 7 is high when its temperature is low and that the permeability gradually decreases with an increase in the temperature.
  • the magnetic compensating alloy member 7 decreases the magnetic flux 8'for deflecting the electron beam at that particular portion, by which the deflection center 0 of the deflection yoke is shifted forwardly to a position indicated by 0'. Without the alloy member 7, the deflection center stays at the position 0.
  • the temperature of the deflection center mounting portion rises to increase the temperature of the ring-shaped magnetic compensating alloy member 7, its permeability decreases to cause an increase in the reluctance of the alloy member 7, by which the magnetic flux flowing in the alloy member 7 is decreased, thus causing an increase inthe magnetic flux 8 at therear end portion of thedeflection yoke 6, as illustrated in FIG. 5.
  • the deflection center 0 is. shifted rearwardly to a position 0''.
  • the amount of increase or decreasein the magnetic flux caused by the temperature variation is in proportion to the cross-sectional area of the. ring shaped magnetic compensating alloy member 7, so that a suitabl'ejselection of the cross-sectional area of the alloy member 7 leads to the selection of the amount of displacement of the deflection center at a predetermined value.
  • the present example has been described in connection with a'magnetic field in one direction, the ring-shaped magnetic compensating.
  • the deflection center of the deflection yoke is shifted rearwardly in accordance with the temperature rise to compensate for mislanding of the beam.
  • a metal fitting for fixedly mounting the deflection yoke 6 about the picture tube 1 as depicted in FIG. 6 is formed of a magnetic compensating alloy.
  • a metal fitting is used as the ring-shaped magnetic compensating alloy member 7 described above.
  • the metal fitting, indicated by 7 in the figures may be simply a ring-shaped strap such as shown in FIG. 7A in which both ends are bent and clamped, for example, by means of a bolt 9.
  • the metal fitting 7 may be in the form depicted in FIGS.
  • FIG. 6A, 6B and 7B in which it consists of two semicircular members and they are assembled together in the form of a ring and are clamped at their ends by bolts.
  • the metal fitting that is, the ring-shaped magnetic compensating alloy member 7 is mounted onthe picture tube 1 in such a manner that its gap or gaps 9 may lie in parallel relation to the line 2-2 in FIG. 6A for the reason that one portion of the horizontal deflection magnetic field is equally by-passed on both sides of the ring-shaped magnetic compensating alloy member 7.
  • reference numeral 10 designates a horizontal winding and 11 a cover of the deflection yoke 6.
  • the ring-shaped magnetic compensating alloy member 7 need not always be disposed on the outside of the picture tube 1 but it may be placed within the tube 1 in the vicinity of the rear end portion of the deflection yoke. Namely, the alloy member 7 may be mounted on the top end portion of an electron gun devicel2 at a position corresponding to the rear end portion of the deflection yoke as depicted in FIG. 8.
  • FIG. 8 shows one example of this invention as applied to the electron gun device 12 of such single-gun, plural-beam type construction as disclosed in, for example, the U.S. Pat. No. 3,448,316.
  • Reference numeral 13 indicates an electron gun, and 14 deflecting plates by means of which electron beams passing through a main electron lens formed by third, fourth and fifth grids of the electron gun l3 and crossing each other are deflected in predetermined directions.
  • Reference numeral 15 designates bead for holding the deflecting plates 14 and 16 a getter ring.
  • the ring-shaped magnetic compensating alloy member 7 is disposed around, the deflecting plates 14 and the same results as the above-described can be obtained, even if the deflecting plates 14 are formed of a magnetic compensating alloy.
  • a color picture tube comprising an envelope having a face plate, a screen of different phosphors coated on said face plate for emitting light of respective predetermined colors, an electron gun device for generating at least one electron beam directed toward said face plate for impingement on said screen, a beam selecting means disposed adjacent said face plate and having apertures through which said beam can pass to.
  • magnetic deflection means fixed on said envelope and operative to produce magnetic flux for deflecting said beam from a deflector center within said deflection means so as to cause scanning of said screen by said beam
  • a magnetic flux shunting member also fixedly located with respectto said envelope and being disposed adjacent said magnetic deflection means at an axial distance from said deflection center for shunting a portion of said magnetic flux produced by said magnetic deflection means, said flux shunting member having a magnetic permeability that varies with changes in the temperature thereof for varying said portion of the flux which is shunted and axially shifting said deflection center, thereby to compensate for thermal expansion of said beam selecting means.
  • a color picture tube in which said magnetic flux shunting member is'in the form of a ring disposed at the side of said magnetic deflection means remote from said screen and said permeability decreases in accordance with increasing temperature,
  • a color picture tube according to claim 1 in which said flux shunting member is in the interior of said envelope.

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US00862411A 1968-10-09 1969-09-30 Color picture tube with deflection center control Expired - Lifetime US3831051A (en)

Applications Claiming Priority (1)

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JP43073723A JPS4822364B1 (enrdf_load_html_response) 1968-10-09 1968-10-09

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US3831051A true US3831051A (en) 1974-08-20

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US (1) US3831051A (enrdf_load_html_response)
JP (1) JPS4822364B1 (enrdf_load_html_response)
FR (1) FR2020262A1 (enrdf_load_html_response)
GB (1) GB1216287A (enrdf_load_html_response)
NL (1) NL6915187A (enrdf_load_html_response)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4376272A (en) * 1980-11-12 1983-03-08 Hitachi, Ltd. Magnetic field generators for use in electromagnetic focusing type cathode ray tubes
US4377348A (en) * 1980-03-27 1983-03-22 Oki Electric Industry Co., Ltd. Printer head for serial dot printer
US4538128A (en) * 1982-10-05 1985-08-27 Videocolor Deviator for an auto convergent color picture tube and its method of manufacture
US4737752A (en) * 1986-08-11 1988-04-12 Megascan Technology, Inc. Oscilloscope deflection yoke with heat dissipation means
WO2004042767A3 (en) * 2002-11-04 2004-07-15 Lg Philips Displays Display device comprising a deflection unit and a deflection unit for a display device

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2506268C2 (de) * 1975-02-14 1977-01-20 Standard Elektrik Lorenz Ag Ablenksystem fuer farbfernsehbildroehren
NL188484C (nl) * 1978-02-06 1992-07-01 Philips Nv Afbuigjuk voor kleurentelevisiebeeldweergeefbuizen.
NL188373C (nl) * 1978-02-06 1992-06-01 Philips Nv Afbuigjuk voor kleurentelevisiebeeldweergeefbuizen.

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1239704A (fr) * 1959-11-03 1960-08-26 Perfectionnement aux déflexions de télévision
US3234423A (en) * 1960-03-24 1966-02-08 Telefunken Ag Cathode-ray tube with combined clamping and shielding means
US3325758A (en) * 1965-12-08 1967-06-13 Varian Associates Negative temperature coefficient shunt means for magnetic structures
US3408520A (en) * 1966-11-01 1968-10-29 Motorola Inc Temperature responsive means for moving the yoke of a color television receiver to compensate for beam landing error during tube warmup
US3524093A (en) * 1968-04-24 1970-08-11 Helen C Haas Time dependent color purity correction for a color cathode ray tube

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1239704A (fr) * 1959-11-03 1960-08-26 Perfectionnement aux déflexions de télévision
US3234423A (en) * 1960-03-24 1966-02-08 Telefunken Ag Cathode-ray tube with combined clamping and shielding means
US3325758A (en) * 1965-12-08 1967-06-13 Varian Associates Negative temperature coefficient shunt means for magnetic structures
US3408520A (en) * 1966-11-01 1968-10-29 Motorola Inc Temperature responsive means for moving the yoke of a color television receiver to compensate for beam landing error during tube warmup
US3524093A (en) * 1968-04-24 1970-08-11 Helen C Haas Time dependent color purity correction for a color cathode ray tube

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4377348A (en) * 1980-03-27 1983-03-22 Oki Electric Industry Co., Ltd. Printer head for serial dot printer
US4376272A (en) * 1980-11-12 1983-03-08 Hitachi, Ltd. Magnetic field generators for use in electromagnetic focusing type cathode ray tubes
US4538128A (en) * 1982-10-05 1985-08-27 Videocolor Deviator for an auto convergent color picture tube and its method of manufacture
US4737752A (en) * 1986-08-11 1988-04-12 Megascan Technology, Inc. Oscilloscope deflection yoke with heat dissipation means
WO2004042767A3 (en) * 2002-11-04 2004-07-15 Lg Philips Displays Display device comprising a deflection unit and a deflection unit for a display device
US20060273708A1 (en) * 2002-11-04 2006-12-07 L.G. Philips Displays Display device comprising a deflection unit and a deflection unit for a display device

Also Published As

Publication number Publication date
DE1950964A1 (de) 1970-04-30
FR2020262A1 (enrdf_load_html_response) 1970-07-10
GB1216287A (en) 1970-12-16
DE1950964B2 (de) 1976-07-08
NL6915187A (enrdf_load_html_response) 1970-04-13
JPS4822364B1 (enrdf_load_html_response) 1973-07-05

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