EP0415125A1 - Kathodenstrahlröhre - Google Patents

Kathodenstrahlröhre Download PDF

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Publication number
EP0415125A1
EP0415125A1 EP90114987A EP90114987A EP0415125A1 EP 0415125 A1 EP0415125 A1 EP 0415125A1 EP 90114987 A EP90114987 A EP 90114987A EP 90114987 A EP90114987 A EP 90114987A EP 0415125 A1 EP0415125 A1 EP 0415125A1
Authority
EP
European Patent Office
Prior art keywords
magnetic field
pair
gun assembly
electron gun
deflection
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.)
Granted
Application number
EP90114987A
Other languages
English (en)
French (fr)
Other versions
EP0415125B1 (de
Inventor
Takeshi C/O Intellectual Property Div. Fujiwara
Kiyoshi C/O Intellectual Property Div. Tokita
Masatsugu C/O Intellectual Property Div. Inoue
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.)
Toshiba Corp
Original Assignee
Toshiba 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 JP20244689A external-priority patent/JP2862575B2/ja
Priority claimed from JP25210589A external-priority patent/JP2859900B2/ja
Application filed by Toshiba Corp filed Critical Toshiba Corp
Publication of EP0415125A1 publication Critical patent/EP0415125A1/de
Application granted granted Critical
Publication of EP0415125B1 publication Critical patent/EP0415125B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • H01J29/46—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
    • H01J29/703—Static 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
    • H01J29/70—Arrangements for deflecting ray or beam
    • 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
    • H01J29/566—Arrangements for controlling cross-section of ray or beam; Arrangements for correcting aberration of beam, e.g. due to lenses for correcting aberration
    • 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
    • H01J29/76—Deflecting by magnetic fields only

Definitions

  • the present invention relates to a color cathode ray tube which improves deflection aberration produced by a deflection magnetic field generated by a deflection unit, i.e., distortion of a beam spot, thereby improving focusing characteristics, and the deflection unit.
  • a color cathode ray tube has an envelope 3 constituted by a panel 1 and a funnel 2.
  • a phosphor screen 5 consisting of three color phosphor layers for emitting blue, green, and red light rays is formed on the inner surface of the panel 1, and a shadow mask 4 is arranged to oppose the phosphor screen 5.
  • An electron gun assembly 7 for emitting three electron beams B, G, and R is arranged in a neck 6 of the funnel 2.
  • the three electron beams B, G, and R are horizontally and vertically deflected by a defection unit 9 mounted outside a boundary portion between a conical portion 8 and the neck 6 of the funnel 2, thereby scanning the phosphor screen 5.
  • a color image is displayed on the phosphor screen 5.
  • the deflection unit 9 has a pair of horizontal deflection coils 10 for horizontally deflecting the three electron beams and a pair of ver­tical deflection coils 11 for vertically deflecting them.
  • This color cathode ray tube generally uses, as the electron gun assembly 7, an in-line type electron gun assembly emitting three electron beams arranged in line, the center beam G and the pair of side beams B and R emitted from the electron guns passing through the same plane.
  • an auxiliary coil is arranged at the electron gun assembly side of the deflection unit and a current in synchronism with a deflection current flowing through a vertical deflection coil is supplied to the auxiliary coil, thereby generating an intense pin-cushion type magnetic field without using a magnetic member to be coupled to a magnetic field leaking from a rear portion of the deflection unit.
  • a spot of an electron beam on the phosphor screen is still distorted in accordance with deflection. That is, as shown in Fig. 3, a spot 13 of an electron beam deflected by an uniform magnetic field is formed into a substantially true circle on the entire surface of a screen 14. As shown in Fig. 4, however, a spot 13 of an electron beam deflected by a non-uniform magnetic field is distorted into a lateral ellipse hav­ing the horizontal direction as its major axis at the end of the horizontal axis (X axis) of the screen 14. That is, as shown in Fig.
  • the electron beams B, G, and R are distorted by a pin-cushion type horizontal deflection magnetic field 15 such that an upper half of each beam is pushed downward and its lower half is pushed upward by a Lorentz force.
  • a pin-cushion type horizontal deflection magnetic field 15 such that an upper half of each beam is pushed downward and its lower half is pushed upward by a Lorentz force.
  • each of the electron beams B, G, and R is dis­torted into a lateral ellipse having the horizontal direction as its major axis by a barrel type vertical deflection magnetic field 16 such that a right half of each electron beam is pushed to the right and its left half is pushed to the left by a Lorentz force.
  • the auxiliary coil used in the Published Examined Utility Model Application No. 57-45748 uses a current synchronized with a deflection current flowing through the vertical deflection coil, the following problem is posed. That is, when an electron beam is to be defle­cted in the vertical direction, the electron beam is excessively deflected in the vertical direction at the electron gun assembly side of the deflection unit by a magnetic field generated in the horizontal direction on the horizontal axis, and tends to collide against the inner wall of the neck of the funnel. As a result, a portion called a neck shadow which does not emit light rays, because no electron beam reaches there, tends to be formed on the screen.
  • this auxiliary coil is manufactured by winding a coil around a magnetic member, and a current is flowed through the coil. Therefore, this auxiliary coil is expensive as a correction element, and it is difficult to decrease its manufacturing cost.
  • the deflection unit is often used by changing its impedance in accor­dance with the type of a receiver of each set maker, and a current to be flowed through the deflection coil is changed in accordance with the changed impedance. Therefore, in order to allow the auxiliary coil to pro­perly operate with respect to the deflection unit, the specification of the auxiliary coil must be changed in accordance with the impedance of the deflection coil, resulting in poor mass-productivity.
  • a cathode ray tube apparatus comprising: an envelope having a tube axis; an in-line type electron gun assembly, received in the envelope, for emitting a center electron beam and two side beams in the same plane; deflection magnetic field generating means for generating a mainly pin-cushion type deflection magnetic field for deflecting the electron beams in a first direction along the plane and generating a mainly barrel type deflection magnetic field for deflecting the elec­tron beams in a second direction perpendicular to the first direction; a first pair of permanent magnet pieces, each having one and opposite poles, located between the deflection magnetic field generating means and the electron gun assembly and closer to the deflec­tion magnetic field generating means, arranged in the first direction so as to be substantially symmetrical about the tube axis, and faced to each other in such a manner that different polarities are opposed to each other, for constantly generating a pin-cushion type first correction magnetic field; and
  • a cathode ray tube apparatus comprising: an envelope having a tube axis; an in-line type electron gun assembly, received in the envelope, for emitting a center electron beam and two side beams in the same plane; deflection magnetic field generating means for generating a mainly pin-cushion type deflection magnetic field for deflecting the electron beams in a first direction along the plane and generating a mainly barrel type deflection magnetic field for deflecting the elec­tron beams in a second direction perpendicular to the first direction; a first two pair of permanent magnet pieces, each having one and opposite poles, located between the deflection magnetic field generating means and the electron gun assembly and closer to the deflec­tion magnetic field generating means and arranged in the first direction so as to be substantially symmetri­cal about the tube axis, each pair being faced to each other in such a manner that different polarities are opposed to each other, for constantly generating a pin­cushion
  • Fig. 6 shows an embodiment of a color cathode ray tube of self-convergence in-line type.
  • This color cathode ray tube has an envelope 3 constituted by a panel 1 and a funnel 2.
  • a phosphor screen 5 consisting of three color phosphor layers for emitting blue, green, and red light rays is formed on the inner surface of the panel 1 to oppose a shadow mask 4 mounted inside the panel 1 and having a large number of electron beam apertures.
  • An in-line type electron gun assembly 20 (to be described later) for emitting three electron beams B, G, and R aligned in a line passing through the same horizontal plane is arranged in a neck 6 of the funnel 2.
  • a deflection unit 9 is mounted outside a boundary portion between a conical portion 8 and the neck 6 of the funnel 2 to vertically and hori­zontally deflect the three electron beams B, G, and R emitted from the electron gun assembly 20, thereby scan­ning the phosphor screen 5.
  • the deflection unit 9 is of self-convergence type of converging the three electron beams B, G, and R on the phosphor screen 5 by using an inhomogeneous magnetic field. As shown in Fig. 7, for example, the deflection unit 9 has a pair of horizontal deflection coils 23 wound to form a saddle shape and arranged inside a sepa­rator 22, and a pair of vertical deflection coils 25 wound around a core 24 and arranged outside the separa­tor 22.
  • the horizontal deflection coils 23 of the def­lection unit 9 form a mainly pin-cushion type deflection magnetic field for deflecting the three electron beams emitted from the electron gun assembly 20 in the hori­zontal direction, i.e., in the X direction
  • the vertical deflection coils 25 form a mainly barrel type deflection magnetic field for deflecting the three elec­tron beams in the vertical direction perpendicular to the beam aligning direction, i.e., in the Y direction.
  • the "mainly pin-cushion type deflection magnetic field” means a pin-cushion type deflection magnetic field as a whole
  • the "mainly barrel type deflection magnetic field” means a barrel type deflec­tion magnetic field as a whole.
  • the pair of permanent magnets 27a and 27b are arranged on an end portion 26 at the electron gun assembly side of the deflection unit 9 in the left-to-right direction, i.e., the horizontal direction so as to be symmetrical about a tube axis Z with different polarities being opposed each other.
  • the pair of permanent magnets 29a and 29b are arranged at a position 28 sepa­rated from the permanent magnets 27a and 27b toward the electron gun assembly with a predetermined interval the­rebetween in the upper-to-lower direction, i.e., the vertical direction so as to be symmetrical about the tube axis Z with different polarities being opposed each other.
  • This arrangement of the permanent magnets 27a, 27b, 29a, and 29b provides the following effect.
  • the vertically arranged permanent magnets 29a and 29b generate an intense pin­cushion magnetic field 31 on an electron beam path between the electron gun assembly 20 and the deflection unit 9 in correspondence with a barrel type deflection magnetic field 30 generated by the vertical deflection coils, thereby producing a Lorentz force, applied in a direction opposite to that of a Lorentz force applied from the barrel type vertical deflection magnetic field on electron beams, for distorting the electron beam spot into an ellipse having the vertical direction as its major axis, and correcting a phenomenon in which spots of the pair of side beams are inclined.
  • the permanent magnets 27a and 27b arranged in the left-to-right direction so as to be separated from the upper and lower permanent magnets 29a and 29b toward the phosphor screen with a predetermined interval therebetween generate a pin-cushion type mag­netic field 33 in the same direction as that of the pin­cushion type magnetic field 32 on the electron beam path between the electron gun assembly 20 and the deflection unit 9.
  • the upper, lower, left, and right permanent magnets 29a, 29b, 27a, and 27b are arranged such that different polarities are opposed each other. Therefore, as shown in Fig. 10, the permanent magnets 27a and 27b generate magnetic fields 34 between the adjacent permanent mag­nets 29a and 29b, respectively in a space in the tube axis direction. These magnetic fields 34 apply a Lorentz force on the side beams B and R in a direction opposite to the direction along which spots of the side beams are inclined by the barrel type vertical deflec­tion magnetic field, thereby correcting the inclination of the spots of the side beams B and R at the phosphor screen vertical end portion caused by the barrel type deflection magnetic field.
  • the pin-cushion type magnetic field 33 gener­ated by the left and right permanent magnets 27a and 27b applies, to the electron beams, Lorentz forces 38 and 39 for distorting a beam spot into an ellipse having its major axis in the horizontal direction. Therefore, by properly setting the magnetization intensities of the magnets 29a and 29b and the magnets 27a and 27b, a beam spot of each of the three electron beams at the central portion of the phosphor screen can be formed into a sub­stantially circle.
  • the in-line type elec­tron gun assembly in which a center beam and a pair of side beams are aligned in a line on the same plane as shown in Fig.
  • the upper and lower permanent magnets 29a and 29b are arranged at a position separated from the left and right permanent magnets 27a and 27b with a predetermined interval therebetween as shown in Fig. 7, inhomogeneity between the ellipticities of the center beam G and the side beams B and R can be corrected. That is, as shown in Fig. 14, each electron beam is emitted from the electron gun assembly 20 and incident on the central portion of the phosphor screen while it is slightly diverged on the vertical plane.
  • a Lorentz force applied by the pin-cushion magnetic field to the electron beams is weaker than that applied to the elec­tron beams when the magnets 29a and 29b are arranged in an area 41.
  • a beam spot of particularly the center beam G can be prevented from being distorted into a longitudinal ellipse having its major axis in the vertical direction.
  • the pair of side beams B and R are emitted obliquely from the electron gun assembly 20 so as to be converged at one point at the center of the phosphor screen 5.
  • the side beams are moved closer to the center beam G, i.e., the tube axis Z than in the area 40. Therefore, when the magnets 27a and 27b are arranged in the area 41, since a Lorentz force applied by the pin-cushion mag­netic field generated by the magnets 27a and 27b is weaker than that obtained when the magnets 27a and 27b are arranged in the area 40, the side beams B and R pass through an area having a weak Lorentz force. As a result, the electron beam spots of the side beams can be prevented from being distorted into a lateral ellipse having its major axis in the horizontal direction.
  • the pair of left and right perma­nent magnets 27a and 27b are arranged at the end portion of the electron gun assembly side of the deflection unit 9.
  • the present invention is not limited to the above embodiment.
  • a pair of permanent magnets 27a and 27b may be arranged near a core 24 of a deflection unit 9.
  • pairs of permanent magnets 29a and 29b, and 27a and 27b can be arranged in an area in which an electron beam is diverged to increase its beam diameter, i.e., can be arranged closer to a phosphor screen. Therefore, an effect of correcting distortion of a beam spot at the vertical end portion of the phosphor screen can be desirably enhanced.
  • permanent magnets 35a and 35b may be arranged in addition to permanent magnets 27a and 27b at a side end portion 26 of an electron gun assembly of a deflection unit 9. That is, two pairs of permanent magnets 35a and 35b, and 27a and 27b each having two poles are arranged at a position 41 in verti­cal and horizontal directions, respectively, so as to be symmetrical about the tube axis (Z axis) of the deflec­tion unit 9 with different polarities being opposed each other.
  • a pair of second bipolar permanent magnets 29a and 29b are arranged at a position 40 opposite to and separated from the pair of upper and lower bipolar per­manent magnets 35a and 35b of the first bipolar perma­nent magnets toward the electron gun assembly along the Y axis with a predetermined interval therebetween so that different polarities are opposed each other between the magnets 29a and 29b and the magnets 35a and 35b, respectively.
  • the pairs of upper and lower, and left and right first bipolar permanent magnets 35a and 35b, and 27a and 27b are arranged at the electron gun side end portion 26 with different polari­ties being opposed each other, the following effect similar to that described above can be obtained.
  • the bipolar permanent magnets 35a, 35b, 27a, and 27b generate intense pin­cushion type magnetic fields 31 and 33 projecting into the tube axis, i.e., the path of the three electron beams in a space at the position 41.
  • a spot of an electron beam which reaches the phosphor screen through the pin-cushion type magnetic field 31 generated by the upper and lower bipolar permanent mag­nets is affected by a Lorentz force in a direction oppo­site to that of a Lorentz force applied by the barrel type magnetic field 30 and is distorted into an ellipse having its major axis in the vertical direction, and the permanent magnets 27a and 27b generate magnetic fields 34 between the adjacent permanent magnets 35a and 35b, respectively in a space in the tube axis direction.
  • the pin-cushion type magnetic fields 31 and 33 generated by the first permanent magnets 27a, 27b, 35a, and 35b on a beam spot formed at the center of the phosphor screen will be described below.
  • the first upper and lower permanent magnets 35a and 35b described above with reference to Fig. 11 generate a pin-cushion magnetic field similarly to the second upper and lower permanent magnets 29a and 29b.
  • This pin-­cushion magnetic field applies, to an electron beam, a Lorentz force for distorting a beam spot into an ellipse having its major axis in the vertical direction on the screen.
  • the pin cushion magnetic field gener­ated by the first left and right permanent magnets 27a and 27b applies, to an electron beam, a Lorentz force for distorting a beam spot into an ellipse having its major axis in the horizontal direction on the screen. Therefore, by properly setting the magnetization inten­sities of the upper and lower magnets 35a and 35b and the left and right magnets 27a and 27b, beam spots of the three electron beams can be formed into substan­tially true circles at the central region of the phos­phor screen. As described above with reference to Fig.
  • the second bipolar permanent magnets 29a and 29b are separated from the upper and lower bipolar permanent magnets 35a and 35b of the first bipolar permanent magnets toward the electron gun assem­bly with a predetermined interval therebetween such that different polarities oppose each other between the two pairs of permanent magnets. Therefore, the polarity of a pin-cushion magnetic field generated by the magnets 29a and 29b is opposite to that of the pin-cushion mag­netic field 31 generated by the magnets 35a and 35b.
  • the direction of a Lorentz force applied to electron beams by the pin-cushion magnetic field gener­ated by the magnets 29a and 29b is opposite to that of a Lorentz force applied by the pin-cushion magnetic field 31 generated by the magnets 35a and 35b, and a beam spot is distorted into an ellipse having its major axis in the horizontal direction. Therefore, by setting the magnetization intensity of the magnets 29a and 29b to be smaller than that of the magnets 35a and 35b, a beam spot of the center beam can be corrected into a true circle without distortion in beam spots of the pair of side beams separated from the tube axis as shown in Fig. 16. As shown in Fig.
  • an electron beam is emitted from the electron gun assembly 20 and incident at the center of the phosphor screen 5 while it is slightly deverged. Therefore, the electron beam diame­ter 41 obtained in an area to which the pin-cushion mag­netic field generated by the magnets 35a and 35b is applied, is larger than the electron beam diameter 40 obtained in an area to which the pin-cushion magnetic field generated by the magnets 29a and 29b is applied. In addition, the intensity of the pin-cushion magnetic field generated by the magnets 35a and 35b is larger than that of the magnetic field generated by the magnets 29a and 29b.
  • the magnets 29a and 29b only correct the beam spot of the center beam into a true circle but do not interfere with an effect of the pin-cushion magnetic field generated by the magnets 35a and 35b for correcting distortion of beam spots and inclination of side beams at the vertical axis end of the phosphor screen.
  • the first permanent magnets 35a, 35b, 27a, and 27b have an effect on the three elec­tron beams. That is, a magnetic field 51 generated by the upper and lower permanent magnets 35a and 35b applies a Lorentz force 53 to the center beam G upon vertical deflection, thereby deflecting the center beam G outwardly. A magnetic field 52 applies a Lorentz force 54 to the side beams B and R, thereby returning the electron beams toward the center.
  • the second permanent magnets 27a and 27b by correcting the beam spot of the center beam by the second permanent magnets 27a and 27b, good focusing characteristics can be obtained, and coma aberration in convergence can be corrected. Because as compared with a magnetic field area of the first permanent magnets 35a, 35b, 26a, and 26b, a vertical magnetic field is small and hardly deflected in a magnetic field of the second permanent magnets. Therefore, the second perma­nent magnets have almost no influence on coma aberration in convergence.
  • the second bipolar permanent magnets for correcting distortion in a beam spot of an electron beam at the center of the phosphor screen are arranged to oppose the pair of upper and lower bipolar permanent magnets of the two pairs of upper and lower, and left and right bipolar permanent magnets arranged at the side end portion of the electron gun assembly side of the deflection unit and are separated therefrom toward the electron gun assembly with a predetermined interval therebetween.
  • the second bipolar permanent magnets can be arranged to oppose the pair of bipolar permanent magnets 27a and 27b in the horizontal direction of the first bipolar permanent mag­nets and separated therefrom toward the electron gun assembly with a predetermined interval therebetween.
  • the magnitudes of magnetization intensities of the magnets 35a, 35b, 27a, and 27b are preferably set such that a beam spot of a center beam is formed into a substantially true circle and that of each of a pair of side beams is distorted into an ellipse having its major axis in the horizontal direction by pin-cushion magnetic fields generated by the magnets.
  • a pin-cushion magnetic field generated by the second bipolar permanent magnets 29a and 29b only cor­rects the shape of the beam spot of each side beam into a true circle but does not interfere with an effect of a pin-cushion magnetic field generated by the upper and lower bipolar permanent magnets 35a and 35b for correct­ing distortion in beam spot at the vertical axis end of the phosphor screen and for correcting coma aberration of the convergence.
  • first bipolar permanent magnets are arranged at the end portion of the electron gun assembly side of the deflection unit.
  • the present invention is not limited to this arrangement.
  • first permanent mag­nets may be arranged at a portion 26 close to a core 23 of a deflection unit 9.
  • first bipolar permanent magnets 35 and 27 are located in an area in which the diameter of an electron beams is large because the beam is deverged. Therefore, an effect of correct­ing distortion in beam spot at the vertical axis end of the phosphor screen can be further enhanced.
  • the second bipolar magnets for correcting distortion in electron beam at the center of the phosphor screen are separated from the first bipolar permanent magnets toward the electron gun of the deflection unit by a predetermined interval therebetween.
  • the present invention is not limited to this arrangement.
  • these magnets may be arranged inside a convergence cup 42 at the distal end portion of an elec­tron gun assembly 20. In this case, since an interval with respect to first bipolar permanent magnets arranged in a deflection unit 9 can be further increased, distor­tion in electron beam spot at the center of a phosphor screen can be corrected better.
  • a pair of left and right permanent magnets are arranged at the end portion of the electron gun assembly side of the deflection unit for generating a deflection magnetic field for deflecting three elec­tron beams aligned in a line passing through the same plane, in the beam aligning direction of the beams and a direction perpendicular to the beam aligning direction, and a pair of upper and lower permanent magnets for generating a pin-cushion magnetic field are arranged to be separated from the end portion of the electron gun assembly side toward the electron gun assembly by a predetermined interval.
  • pairs of upper and lower, and left and right bipolar permanent magnets are arranged at the end portion of the electron gun assembly side of the deflection unit for generating a deflection magnetic field for deflecting three electron beams aligned in a line passing through the same plane, in the beam aligning direction of the beams and a direction perpendicular to the beam aligning direction, and a pair of bipolar permanent magnets for generating a pin-cushion magnetic field are arranged to be separated from the side end portion of the electron gun assembly toward the electron gun assembly.
  • distortion in electron beam spot caused by a barrel type magnetic field generated by a vertical deflection coil can be corrected by the pin-cushion magnetic fields generated by the three pairs of bipolar permanent magnets, thereby improving focusing perform­ance at the vertical axis end portion of the phosphor screen.
  • inhomogeneity between beam spots of the three electron beams at the central portion of the phosphor screen can be connected to improve focusing performance at the central portion of the phosphor screen.

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  • Video Image Reproduction Devices For Color Tv Systems (AREA)
EP90114987A 1989-08-04 1990-08-03 Kathodenstrahlröhre Expired - Lifetime EP0415125B1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP202446/90 1989-08-04
JP20244689A JP2862575B2 (ja) 1989-08-04 1989-08-04 カラー受像管
JP25210589A JP2859900B2 (ja) 1989-09-29 1989-09-29 カラー受像管
JP252105/90 1989-09-29

Publications (2)

Publication Number Publication Date
EP0415125A1 true EP0415125A1 (de) 1991-03-06
EP0415125B1 EP0415125B1 (de) 1996-10-23

Family

ID=26513377

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90114987A Expired - Lifetime EP0415125B1 (de) 1989-08-04 1990-08-03 Kathodenstrahlröhre

Country Status (4)

Country Link
EP (1) EP0415125B1 (de)
KR (1) KR930004108B1 (de)
CN (1) CN1018408B (de)
DE (1) DE69028968T2 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0421523B1 (de) * 1989-10-02 1995-06-28 Koninklijke Philips Electronics N.V. Farbbildröhrensystem mit reduziertem Fleckwachstum

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
MY120102A (en) * 1995-02-28 2005-09-30 Toshiba Kk A deflection unit having a distortion correcting coil in a cathode ray tube apparatus

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4197487A (en) * 1977-06-08 1980-04-08 Tokyo Shibaura Denki Kabushiki Kaisha Beam-index tube apparatus having deflection field correcting elements
US4818919A (en) * 1986-10-31 1989-04-04 Kabushiki Kaisha Toshiba Color picture tube apparatus

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4197487A (en) * 1977-06-08 1980-04-08 Tokyo Shibaura Denki Kabushiki Kaisha Beam-index tube apparatus having deflection field correcting elements
US4818919A (en) * 1986-10-31 1989-04-04 Kabushiki Kaisha Toshiba Color picture tube apparatus

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, unexamined applications, E field, vol. 11, no. 275, September 5, 1987 THE PATENT OFFICE JAPANESE GOVERNMENT page 85 E 537 * JP - A - 62 - 76 140 ( MITSUBISHI ELECTRIC ) * *
PATENT ABSTRACTS OF JAPAN, unexamined applications, E field, vol. 12, no. 77, March 10, 1988 THE PATENT OFFICE JAPANESE GOVERNMENT page 136 E 589 * JP - A - 62 -217 546 ( MATSUSHITA ELECTRONICS )* *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0421523B1 (de) * 1989-10-02 1995-06-28 Koninklijke Philips Electronics N.V. Farbbildröhrensystem mit reduziertem Fleckwachstum

Also Published As

Publication number Publication date
DE69028968T2 (de) 1997-04-03
CN1018408B (zh) 1992-09-23
DE69028968D1 (de) 1996-11-28
KR910005366A (ko) 1991-03-30
EP0415125B1 (de) 1996-10-23
KR930004108B1 (ko) 1993-05-20
CN1049751A (zh) 1991-03-06

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