EP1294009A2 - Cacon d'électron pour tube à rayons cathodiques couleur - Google Patents

Cacon d'électron pour tube à rayons cathodiques couleur Download PDF

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Publication number
EP1294009A2
EP1294009A2 EP02254610A EP02254610A EP1294009A2 EP 1294009 A2 EP1294009 A2 EP 1294009A2 EP 02254610 A EP02254610 A EP 02254610A EP 02254610 A EP02254610 A EP 02254610A EP 1294009 A2 EP1294009 A2 EP 1294009A2
Authority
EP
European Patent Office
Prior art keywords
electron gun
focus
electrodes
electrode
voltage
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.)
Withdrawn
Application number
EP02254610A
Other languages
German (de)
English (en)
Other versions
EP1294009A3 (fr
Inventor
Youn Jin Migwang Apt. 101-413 Kim
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.)
LG Philips Displays Korea Co Ltd
Original Assignee
LG Philips Displays Korea Co 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 LG Philips Displays Korea Co Ltd filed Critical LG Philips Displays Korea Co Ltd
Publication of EP1294009A2 publication Critical patent/EP1294009A2/fr
Publication of EP1294009A3 publication Critical patent/EP1294009A3/fr
Withdrawn legal-status Critical Current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
    • H01J29/48—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
    • 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
    • H01J29/58—Arrangements for focusing or reflecting ray or beam
    • 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
    • H01J2229/5688—Velocity modulation

Definitions

  • the present invention relates to an electron gun for a color cathode ray tube (CRT), and in particular to an electron gun for a color CRT with an improved electrode structure and shape in order to reduce a spot diameter influencing a focus of an electron beam.
  • CTR color cathode ray tube
  • Fig. 1 is a schematic structure view illustrating a related CRT.
  • a plurality of electrodes are formed on an in-line electron gun for the CRT.
  • the plurality of electrodes are positioned at predetermined intervals in a vertical direction to a path of an electron beam 13, so that the electron beam 13 generated in cathodes 3 can reach a screen 17 in a predetermined strength.
  • the plurality of electrodes include a first electrode 4 which is a common lattice of three cathodes 3 and another three cathodes 3 arranged separately from the cathodes 3, a second electrode 5 arranged at a predetermined interval from the first electrode 4, a third electrode 6, a fourth electrode 7, a fifth electrode 8 and a sixth electrode 9.
  • a shield cup 10 having a BSC 11 for electrically connecting the electron gun to the tube and fixing the electron gun to a neck unit of the tube is formed on the sixth electrode 9.
  • the operation of the electron gun will now be explained.
  • electrons are emitted from stem pins 1 by a heater 2 of the cathode 3.
  • the electron beam 13 is controlled by the first electrode 4 which is a control electrode, accelerated by the second electrode 5 which is an accelerating electrode, and partially focused and accelerated by a full space focus lens formed among the second electrode 5, the third electrode 6, the fourth electrode 7 and the fifth electrode 8.
  • the electron beam is mostly focused and accelerated by the sixth electrode 9 which is synchronized with a deviation signal to form a quadrupole lens for compensating for astigmatism generated by a deflection yoke, which receives a variable voltage and which is a main lens formation electrode called a focus electrode, and the seventh electrode 10 which is an anode electrode, passes through a shadow mask 15 formed inside a fluorescent surface 16, and collides the fluorescent surface 16, to emit light.
  • the deflection yoke 12 for deviating the electron beam 13 emitted from the electron gun to the whole surface of the screen 17 is positioned outside the electron gun, thereby embodying the screen.
  • a velocity modulation (VM) coil 18 synchronized with an image signal of a circuit is formed on the neck unit of the CRT having the related electron gun.
  • the VM coil 18 is used to reduce the spot diameter.
  • a lens magnification, a space charge repulsive force and a spherical aberration of a main lens influence the spot diameter of the screen.
  • the variation of the spot diameter D x due to the lens magnification is rarely used as a design factor of the electron gun and less effective, since basic voltage conditions, a focal distance and a length of the electron gun are previously determined.
  • the space charge repulsive force is a spot diameter magnification phenomenon resulting from repulsion and collision of electrons of the electron beam.
  • a progressing angle of the electron beam (hereinafter, referred to as 'divergence angle'; ⁇ ) is preferably set up to be increased.
  • the spot diameter D ic is magnified due to difference in the focal distance between electrons passing through a radical axis of the lens and electrons passing through a protaxis thereof. Oppositely to the space charge repulsive force, when the divergence angle of the electron beam incident on the main lens is decreased, the spot diameter is embodied small on the screen.
  • the diameter of the main lens is magnified, if an electron beam having a large divergence angle is incident, magnification of the spots due to the spherical aberration is restricted, and the space charge repulsive force after passing through the main lens unit is decreased, thereby embodying small spots on the screen.
  • Fig. 2 is an experimental result showing variations of the spot diameter by the main lens diameter.
  • the fifth electrode receiving a high voltage and the sixth electrode synchronized with the deviation signal for receiving a variable voltage are called focus electrodes.
  • a length of the focus electrode is an important factor for determining a voltage ratio (%: focus/high voltage) of the electron gun.
  • the sixth electrode is used to compensate for astigmatism of the deflection yoke. When it is not necessary to improve resolution and clearness of a peripheral screen unit, the sixth electrode may not be employed.
  • a method for mechanically magnifying a hole diameter of a main lens formation electrode and a method for increasing a depth of an electrostatic field control electrode for correcting a lens have been taught as methods for magnifying a main lens unit.
  • a circuit of a chassis driving the CRT is appropriately controlled to reduce the spot diameter on the screen and improve resolution, so that a differential signal of an image signal for scanning the electron beam to the screen is synchronized with the coil of the neck unit of the CRT having the electron gun, and the electron beam is evenly modulated in a deviation speed by a deviation magnetic field of the deflection yoke.
  • resolution and clearness of the screen are improved.
  • Fig. 3 is a schematic view illustrating an operation principle of the VM coil.
  • a whole length of the electrode receiving a fixed focus voltage must be sufficiently short, and an interval must be sufficiently prepared so that a speed modulation magnetic field due to current synchronized with the image signal of the coil can be efficiently penetrated thereinto.
  • the structure of the related electron gun is not suitable to maximize the effect of the coil.
  • a center of the magnetic field generated by the coil is positioned adjacently to the fifth electrode receiving a relatively high voltage.
  • a length of the electrode is increased for the required voltage ratio in design.
  • the structure of the electron gun by the simplified long electrode deteriorates speed modulation effects due to the magnetic field of the coil, thus restricting improvement of the resolution.
  • resolution of the screen is improved by minimizing a screen spot diameter by 15 to 30% in a horizontal direction.
  • a length of a focus electrode in which a center of a magnetic field generated by the VM coil is positioned and which receives a fixed focus voltage must be increased for a high voltage ratio.
  • an interval of electrodes must be sufficiently prepared so that a speed modulation magnetic field due to current synchronized with an image signal of the VM coil can be efficiently penetrated thereinto.
  • an electron gun main lens structure of the preferred embodiment includes electrodes having an opening unit commonly used for three electron beams, a plate-shaped electrostatic field control electrode having three electron beam passing holes, and a plurality of cap-shaped stacked electrodes.
  • the plurality of electrodes are electrically connected by a welding process, for receiving a high voltage and a variable voltage synchronized with a deviation signal.
  • the focus electrodes are divided into an electrode applying a variable focus voltage and electrodes applying a fixed focus voltage.
  • At least two focus electrodes applying the fixed focus voltage are provided.
  • Figs. 4a and 4b are structure views illustrating a related electron gun
  • Fig. 4c is a structure view illustrating an electron gun where the focus electrodes 28 receiving the fixed focus voltage are arranged in a row in accordance with the present invention.
  • Fig. 4d is a structure view illustrating the electron gun in accordance with the present invention.
  • the focus electrode 31 receiving the variable focus voltage and the focus electrodes 28 receiving the fixed focus voltage are arranged in a row.
  • Cathodes 23 receiving an image signal, a second electrode 25 collecting electrons emitted from the cathodes 23 and enabling the electrons to go toward the screen, and a first electrode 24 for preventing emission of the electrons when a voltage corresponding to an image signal for applying the electron beam to the cathode is not transmitted are arranged in the electron gun of Fig. 4c.
  • a third electrode 26 for applying a relatively high voltage, a fourth electrode 27 for applying a relatively low voltage, and focus electrodes 28a, 28b and 28c for applying a relatively high fixed voltage are also arranged therein.
  • the main lens is formed to scan the electron beam to the screen by a ninth electrode 29 receiving a high voltage.
  • the electron gun of Fig. 4d further includes an eighth electrode 31 for forming a quadrupole lens synchronized with a deviation signal of a deflection yoke, for applying the variable focus voltage and compensating for astigmatism generated by a deflection yoke magnetic field.
  • the main lens is formed to scan the electron beam to the screen by the eighth electrode 31 and the ninth electrode 29 receiving the high voltage, thereby forming the screen of the CRT.
  • Fig. 6 is a structure view illustrating the electron gun including the focus electrode for applying the fixed focus voltage in accordance with the present invention.
  • the main electrodes include the anode electrode 29 and the focus electrodes 28.
  • the focus electrodes 28 are composed of the electrode 31 for applying the variable focus voltage, and the electrodes 28 for applying the fixed focus voltage.
  • At least two focus electrodes 28 for applying the fixed focus voltage are arranged in a row.
  • a sum (L) of the length of the focus electrodes 28 ranges from 4mm to 30mm.
  • Figs. 5a to 5c show variations of the spot diameter by the focus electrodes receiving the fixed focus voltage and the coil synchronized with a differential signal of an image signal.
  • Fig. 5a is a graph showing a number of the intervals of the electron gun electrodes, especially the focus electrodes being positioned at the center of a coil operation magnetic field, and receiving the fixed focus voltage, namely a number of the intervals of the fifth electrode 28a, the sixth electrode 28b and the seventh electrode 28c of Fig. 4, and a reduction amount of the screen spot due to a speed modulation magnetic field of the coil.
  • Fig. 5b is a graph showing a length of the intervals of the focus electrodes 28 and the reduction amount of the screen spot due to the speed modulation magnetic field of the coil.
  • the length of the intervals ranges from about 0.6 to 1.2mm, the operation of the coil is maximized.
  • Fig. 5c is a graph showing relation of a total length of the electron gun and the speed modulation magnetic field of the coil.
  • the electron gun inserted into the CRT has a proportional period.
  • the number of the intervals of the focus electrodes 28 is at least one, and the length of the intervals preferably ranges from 0.6 to 1.2mm.
  • the long total length of the electron gun is advantageous, it is not effective over a predetermined level.
  • the size of the spots on the screen can be reduced by about 15 to 30% in a horizontal direction.
  • the whole length of the focus electrode receiving the fixed focus voltage is maintained as it is, the focus electrode is divided into at least two electrodes to apply the identical voltage, and the intervals of the focus electrodes range from 0.6 to 1.2mm, thereby reducing the spot diameter on the screen by 15 to 30% in the horizontal direction.
  • the electron gun can be applied with small expenses and short period, to improve quality of the focus in advance.

Landscapes

  • Details Of Television Scanning (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)
EP02254610A 2001-09-14 2002-07-01 Cacon d'électron pour tube à rayons cathodiques couleur Withdrawn EP1294009A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR2001056933 2001-09-14
KR10-2001-0056933A KR100426569B1 (ko) 2001-09-14 2001-09-14 칼라음극선관용 전자총

Publications (2)

Publication Number Publication Date
EP1294009A2 true EP1294009A2 (fr) 2003-03-19
EP1294009A3 EP1294009A3 (fr) 2004-05-06

Family

ID=19714302

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02254610A Withdrawn EP1294009A3 (fr) 2001-09-14 2002-07-01 Cacon d'électron pour tube à rayons cathodiques couleur

Country Status (4)

Country Link
EP (1) EP1294009A3 (fr)
JP (2) JP2003092071A (fr)
KR (1) KR100426569B1 (fr)
CN (1) CN1206695C (fr)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4728858A (en) * 1986-02-14 1988-03-01 Kabushiki Kaisha Toshiba Color cathode ray tube apparatus
US6031326A (en) * 1997-04-01 2000-02-29 Hitachi, Ltd. Electron gun with electrode supports

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE69724942D1 (de) * 1997-07-04 2003-10-23 Thomson Tubes & Displays Farbbildröhre mit einer in-line Elektronenkanone
JPH11135031A (ja) * 1997-10-30 1999-05-21 Hitachi Ltd カラー陰極線管
KR100339349B1 (ko) * 1999-08-07 2002-06-03 구자홍 칼라 음극선관용 전자총
KR100728190B1 (ko) * 2001-01-17 2007-06-13 삼성에스디아이 주식회사 음극선관용 전자총
KR100778497B1 (ko) * 2001-05-15 2007-11-22 삼성에스디아이 주식회사 음극선관용 전자총

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4728858A (en) * 1986-02-14 1988-03-01 Kabushiki Kaisha Toshiba Color cathode ray tube apparatus
US6031326A (en) * 1997-04-01 2000-02-29 Hitachi, Ltd. Electron gun with electrode supports

Also Published As

Publication number Publication date
JP2003092071A (ja) 2003-03-28
EP1294009A3 (fr) 2004-05-06
KR100426569B1 (ko) 2004-04-08
CN1206695C (zh) 2005-06-15
KR20030023826A (ko) 2003-03-20
JP2005129544A (ja) 2005-05-19
CN1405830A (zh) 2003-03-26

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