WO2002052605A1 - Cathode ray tube with modified in-line electron gun - Google Patents
Cathode ray tube with modified in-line electron gun Download PDFInfo
- Publication number
- WO2002052605A1 WO2002052605A1 PCT/IB2001/002456 IB0102456W WO02052605A1 WO 2002052605 A1 WO2002052605 A1 WO 2002052605A1 IB 0102456 W IB0102456 W IB 0102456W WO 02052605 A1 WO02052605 A1 WO 02052605A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- green
- cathode
- ray tube
- cathode ray
- longitudinal axis
- Prior art date
Links
- 238000010894 electron beam technology Methods 0.000 claims description 25
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 9
- 239000007789 gas Substances 0.000 description 3
- 238000010849 ion bombardment Methods 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 230000032683 aging Effects 0.000 description 2
- -1 argon ions Chemical class 0.000 description 2
- 238000009125 cardiac resynchronization therapy Methods 0.000 description 2
- 230000002730 additional effect Effects 0.000 description 1
- XKRFYHLGVUSROY-UHFFFAOYSA-N argon Substances [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 201000009310 astigmatism Diseases 0.000 description 1
- 238000002845 discoloration Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000005686 electrostatic field Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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
- H01J29/52—Arrangements for controlling intensity of ray or beam, e.g. for modulation
-
- 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
- H01J29/04—Cathodes
-
- 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
Definitions
- the invention relates to a cathode ray tube having a longitudinal axis, a phosphor screen, an electron gun arranged around the longitudinal axis, the electron gun comprising a triode part having three cathodes for generating a red, a green and a blue electron beam, respectively, and two common grids arranged transversely to the longitudinal axis, and a focus lens part having at least two common grids arranged transversely to the longitudinal axis.
- a cathode ray tube for television or other purposes has an envelope with a large bulb portion and a tubular neck portion fixed thereto.
- a plurality of electrodes for forming and focusing electron beams along a path extending into the bulb portion is mounted within the tubular neck portion.
- Magnetic or electrostatic field-producing means are used for moving the electron beams in any desired manner over a wall portion or face plate of the envelope bulb portion.
- the inner surface of the wall or face plate is coated with a film of phosphor material which luminesces with a visible light when struck by the electron beams.
- the setmaker When using a CRT during the manufacture of, e.g. a television set or a monitor, the setmaker has to set the white point. It turns out, however, that the white point of the finalized apparatus is sometimes shifted and displayed images become discolored.
- the cathode ray tube in accordance with the invention is characterized in that the cathode for generating the green electron beam is offset from the longitudinal axis, the electron gun being capable of having the green electron beam in the center of the phosphor screen.
- the invention is based on the recognition that initially, during the adjustments of the cathode ray tube apparatus, the "green" cathode has a temporary loss of emission due to residual gases being present inside the tube and due to ionization of the gas atoms leading to bombardment of the cathode surfaces with positive ions.
- the emission improves substantially after one or two hours of tube operation (scanning aging or raster aging, also called the soak test). As a result, the white point is shifted and displayed images become greener.
- the object of this invention is to obtain a new electron gun design for which the three cathodes are equally exposed to ion bombardment and thus suffer from emission loss with equal severity. This can be achieved by introducing a kink in the "green" electron beam too.
- This kink can be constructed analogously to the kinks in the "red” and “blue” electron beams in either the horizontal direction or the vertical direction. This idea is worked out below for the cathode positions and for the positions of the grid apertures, where a slight offset from the longitudinal axis (z-axis), or from the original in-line plane (the x-z plane) is considered. A delta orientation of the three cathodes can also be considered.
- the kink in the "green" beam requires an electron-gun design in which apertures are made for the green beam in the G2 and/or in the G3a-grid, which are eccentric with respect to the apertures in the Gl grid.
- FIG. 1 is a diagrammatic cross-section of an embodiment of a cathode ray tube for a picture display device
- Fig. 2 shows the positions of the cathodes (and grid apertures) in: (a) a current in-line configuration, (b) the "green” cathode shifted in the horizontal direction, and the "green” cathode shifted (c) in the vertical direction;
- Fig. 3 shows the positions of the cathodes (and grid apertures) in: (a) a current in-line configuration, (b) the three cathodes shifted in the vertical direction by equal amounts, and (c) the green cathode shifted more in the vertical direction than the red and blue cathodes;
- Figs. 4, 5 and 6 are schematic views of electron guns with three electron beams in which the green beam is kinked in three different manners.
- the cathode ray tube shown in Fig. 1 is a color cathode ray tube 1 having an evacuated envelope 2 comprising a display window 3, a cone 4 and a neck 5.
- the neck 5 accommodates an electron gun 6 for generating three electron beams 7, 8 and 9 extending, in this embodiment, in one plane.
- a display screen 10 is situated on the inner side of the display window 3.
- the display screen 10 comprises a plurality of red, green and blue-luminescing phosphor elements. Each group of (red, green or blue) phosphor elements forms a pattern.
- the display screen may alternatively comprise other patterns such as a black matrix (a black pattern) or color filter patterns.
- the electron beams 7, 8 and 9 are deflected across the display screen 10 by means of a deflection unit 11.
- the arrow Z represents the direction of the longitudinal axis of the tube 1
- the arrow X represents the direction of the longitudinal axis of the display screen 10.
- Conventional electron guns of the in-line type have three cathodes which lie in one plane and generate three electron beams lying in that plane (generally the X-Z plane).
- the cathodes in that case have a configuration in accordance with Fig. 2a, the green cathode being aligned with the Z-axis.
- gas atoms present inside the tube can be ionized by high- velocity electrons.
- Positive ions like argon ions, travel in the reverse direction of the electrons generated by the cathodes under the action of the electric field. Bombardment of the cathode surface with positive ions can lead to (temporary or permanent) loss of emission if the area of bombardment and the emitting area coincide. If the loss of emission is not equal for the three cathodes, the problem of white point shift occurs.
- This kink can be constructed analogously to the kinks in the "red” and “blue” electron beams by a translation of the "green” apertures in the triode grids in either the horizontal or the vertical direction. This is shown in Figure 2 for the positions of the cathodes and the grid
- FIG. 2 A delta orientation of the three cathodes can also be considered.
- a translation of the three cathodes in the vertical direction can be considered, as is shown in Figure 3.
- the dotted line represents the original in-line plane (X-Z plane)
- Figs. 2a and 3 a represent the conventional "3 -in-line" cathode configuration in which the central (green) beam goes straight to the phosphor screen, without a kink in its trajectory.
- a kink is involved. The applicability and effectiveness of these kinks plus the magnitude of the translation of the green beam depend on the specific tube and electron gun.
- the central (green) cathode is slightly offset in the vertical direction from the original in-line plane.
- configuration 1(b) cannot give the desired effect completely, because there is insufficient space to shift the "green" cathode, and because the convergence of the electron beams is disturbed.
- Fig. 3b the plane of the three cathodes is offset from the original in-line plane.
- Fig. 3 c the plane of the three cathodes is offset from the original in-line plane, and the central (green) cathode has an additional offset in the vertical direction.
- the configurations shown in Figs. 2b, 2c, 3b and 3c involve a kink in the trajectory of the green beam.
- Fig. 4 schematically shows an electron gun in which the trajectory of the electron beam 41 generated by the green cathode G gets a kink in grid G3a for convergence with the red and blue beams in the center of the screen.
- Fig. 5 An alternative is shown in Fig. 5, where the trajectory of the green beam 42 has two kinks, one near grid 3 A in the pre-focusing section, and one before entering the area of the main lens 20, 21 e.g. in the DAF or DAF-DBF section, such that the green beam passes straight through the center of the main lens 20, 21. This may overcome convergence problems.
- the kink near grid G3a in the prefocusing section is not much susceptible to the variation of the dynamic focusing potential, because the potential difference between grids G2 and G3a is of the order of several kV. Creating a kink in the DAF or DBF sections is more difficult, because the potential differences over these gaps vary between -300 and 1000V. Of course, this only applies to DAF and DAF-DBF guns and not to non-DAF electron guns.
- FIG. 6 Another alternative, shown in Fig. 6, is creating a first kink in the triode section between grids Gl and G2, and a second kink near grid G3a. Also in this case, the green beam passes straight through the center of the main lens 20, 21.
- DAF is used in the prior art to indicate a dynamic astigmatism focus lens
- DBF is used to indicate a dynamic beam focus lens
- the pitch of the outer grid apertures (the apertures for the red and the blue beam) in the triode part is 6.020 mm and the pitch of the outer apertures in grid G3a is 5.080 mm.
- the desired "kink” in the trajectories of the red and the blue beam is achieved by this "eccentricity".
- a kink can be achieved in the trajectory of the central (green) beam.
- the invention relates to a cathode ray tube having an electron gun which is modified with respect to the electron gun having three equidistant cathodes lying "in line".
- the cathode for generating the green (central) beam is offset with respect to its position in an in-line gun, and the grids in the focus and/or triode part of the gun have been modified to provide at least one kink in the trajectory of the green beam to restore convergence.
- I-cathodes As cathodes of the impregnated type, so-called I-cathodes, are particularly sensitive to ion bombardment, the invention is particularly suitable for use in CRTs which are equipped with I-cathodes.
Landscapes
- Electrodes For Cathode-Ray Tubes (AREA)
- Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
- Video Image Reproduction Devices For Color Tv Systems (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2002553212A JP2004516636A (en) | 2000-12-22 | 2001-12-07 | CRT with modified in-line electron gun |
EP01272154A EP1346392A1 (en) | 2000-12-22 | 2001-12-07 | Cathode ray tube with modified in-line electron gun |
KR1020027010775A KR20020072587A (en) | 2000-12-22 | 2001-12-07 | Cathode ray tube with modified in-line electron gun |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP00204784 | 2000-12-22 | ||
EP00204784.3 | 2000-12-22 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2002052605A1 true WO2002052605A1 (en) | 2002-07-04 |
Family
ID=8172543
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IB2001/002456 WO2002052605A1 (en) | 2000-12-22 | 2001-12-07 | Cathode ray tube with modified in-line electron gun |
Country Status (7)
Country | Link |
---|---|
US (1) | US6744190B2 (en) |
EP (1) | EP1346392A1 (en) |
JP (1) | JP2004516636A (en) |
KR (1) | KR20020072587A (en) |
CN (1) | CN1404616A (en) |
TW (1) | TW543067B (en) |
WO (1) | WO2002052605A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2006084897A2 (en) * | 2005-02-10 | 2006-08-17 | Lg.Philips Displays Holding B.V. | Electron gun and cathode ray tube |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1405901A (en) * | 1971-09-23 | 1975-09-10 | Licentia Gmbh | Cathode ray tubes for displaying colour television pictures |
JPH1173892A (en) * | 1997-08-29 | 1999-03-16 | Sony Corp | Electron gun for color cathode ray tube |
EP1032018A2 (en) * | 1999-02-24 | 2000-08-30 | Sony Corporation | Electron gun, color cathode ray tube, and display apparatus using same |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4374609A (en) * | 1981-05-21 | 1983-02-22 | Zenith Radio Corporation | Image projection screen with decreased color shift as a function of viewing angle, and method of manufacture |
US6479937B2 (en) * | 2001-03-13 | 2002-11-12 | Chunghwa Picture Tubes, Ltd. | Multi-beam index CRT with horizontal phosphor lines |
-
2001
- 2001-09-24 TW TW090123474A patent/TW543067B/en not_active IP Right Cessation
- 2001-12-07 JP JP2002553212A patent/JP2004516636A/en active Pending
- 2001-12-07 CN CN01805463A patent/CN1404616A/en active Pending
- 2001-12-07 EP EP01272154A patent/EP1346392A1/en not_active Withdrawn
- 2001-12-07 KR KR1020027010775A patent/KR20020072587A/en not_active Application Discontinuation
- 2001-12-07 WO PCT/IB2001/002456 patent/WO2002052605A1/en not_active Application Discontinuation
- 2001-12-20 US US10/024,771 patent/US6744190B2/en not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1405901A (en) * | 1971-09-23 | 1975-09-10 | Licentia Gmbh | Cathode ray tubes for displaying colour television pictures |
JPH1173892A (en) * | 1997-08-29 | 1999-03-16 | Sony Corp | Electron gun for color cathode ray tube |
EP1032018A2 (en) * | 1999-02-24 | 2000-08-30 | Sony Corporation | Electron gun, color cathode ray tube, and display apparatus using same |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 1999, no. 08 30 June 1999 (1999-06-30) * |
Also Published As
Publication number | Publication date |
---|---|
CN1404616A (en) | 2003-03-19 |
KR20020072587A (en) | 2002-09-16 |
US6744190B2 (en) | 2004-06-01 |
EP1346392A1 (en) | 2003-09-24 |
JP2004516636A (en) | 2004-06-03 |
US20020079816A1 (en) | 2002-06-27 |
TW543067B (en) | 2003-07-21 |
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