EP0125949B1 - Farbfernsehröhre mit einer Korrektur von Komafehlern geringer Amplitude - Google Patents

Farbfernsehröhre mit einer Korrektur von Komafehlern geringer Amplitude Download PDF

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Publication number
EP0125949B1
EP0125949B1 EP84400706A EP84400706A EP0125949B1 EP 0125949 B1 EP0125949 B1 EP 0125949B1 EP 84400706 A EP84400706 A EP 84400706A EP 84400706 A EP84400706 A EP 84400706A EP 0125949 B1 EP0125949 B1 EP 0125949B1
Authority
EP
European Patent Office
Prior art keywords
coma
correction
horizontal
beams
dimension
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
Application number
EP84400706A
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English (en)
French (fr)
Other versions
EP0125949A1 (de
Inventor
Roger Pieri
Jacques Baudry
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.)
Videocolor SA
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Videocolor SA
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 Videocolor SA filed Critical Videocolor SA
Priority to AT84400706T priority Critical patent/ATE28012T1/de
Publication of EP0125949A1 publication Critical patent/EP0125949A1/de
Application granted granted Critical
Publication of EP0125949B1 publication Critical patent/EP0125949B1/de
Expired legal-status Critical Current

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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
    • H01J29/707—Arrangements intimately associated with parts of the gun and co-operating with external magnetic excitation devices
    • 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

Definitions

  • the invention relates to a display tube, in particular a television, in color of the self-converging type with three beams of coplanar electrons.
  • tube here is meant the system constituted by the tube proper, the deflector and the electron beam generators.
  • color images are usually obtained using a screen covered with luminescent substances of three fundamental colors, generally red, green and blue, which are excited by three electron beams, one for each color. These beams converge on the screen and are moved in lines from left to right and from top to bottom.
  • the screen is made up of triads, that is, sets of three dots, luminescent substances of the three colors.
  • the light intensity (luminance) and the color of each point of the image to be reproduced are obtained by the intensity of excitation of each of the elements of the triad.
  • each electron beam reaches only the points of the color to which it is assigned, on the one hand the three beams have different directions and, on the other hand, a shadow mask is placed in front of the screen.
  • the displacement of the beams along lines which is called scanning, is produced by two variable magnetic fields which deflect the beams one in the horizontal direction and the other in the vertical direction. These magnetic fields are generated by electric currents of variable intensity flowing in coils called deflectors.
  • the magnetic field through which these beams pass must have a particular non-uniform configuration in space, which is linked in particular to the rectangular and substantially planar shape of the screen and the coplanar arrangement of the beams.
  • the tube When convergence is obtained exclusively by the configuration of the magnetic field, the tube is said to be self-converging.
  • This autoconvergence is achieved mainly thanks to the shape of the windings of the deflector.
  • the conformation of these windings is generally not sufficient: there are usually convergence faults.
  • One of these is the so-called coma defect which results, in a tube with coplanar beams, by dimensions of the image produced by the central beam (generally green) different from the dimensions of the image produced by the lateral beams (red and blue). This defect is measured by the distance separating two adjacent vertical edges from the green and red-blue images and by the distance separating two adjacent horizontal edges from these images.
  • the invention relates to the case where the coma defect is of small amplitude, that is to say of the order of a millimeter or less, and of different directions in the horizontal (east-west) and vertical (north- south), the image (green) produced by the central beam being for example wider than the image produced by the lateral beams (red-blue) but of lower height than that of this image produced by the lateral beams.
  • the invention results from the observation that the magnetic pieces of coma correction known up to now are not suitable for the correction of this type of defect.
  • the magnetic elements are constituted by magnetic pads applied to the bottom of a cup constituting an electrode for outputting the electron guns, and which therefore has three openings for the passage of bundles, two of these pellets having the form of crowns or washers surrounding the openings provided for the lateral beams, two other pellets being elongated vertical bars placed on either side of the opening for the green central beam.
  • These magnetic elements are suitable for coma defects of large amplitude, 5 mm for example; but for faults of smaller amplitude they confer a correction of too high a value which causes a fault in the opposite direction.
  • coma defect correction elements comprise four plates of rectangular shape and whose plane is perpendicular to the axis of the tube, these plates being arranged above and below each of the lateral beams, with in addition perpendicular plates, with a plane parallel to the axis of the tube on each side of the central beam.
  • Such a configuration also does not make it possible to correct the defect in a coma of low amplitude, of the order of a millimeter or less and of different directions in the horizontal and vertical directions.
  • the tube according to the invention is characterized in that the magnetic coma correction elements, which are also flat patches, with a plane perpendicular to the direction of the beams, consist exclusively of four rectangular patches, preferably all identical, associated with the lateral beams , two of these pellets being below these respective beams and the other two pellets above these same beams, the length and the width of each patch being chosen as a function of the respective values of the coma defects in vertical and horizontal direction to correct.
  • the magnetic coma correction elements which are also flat patches, with a plane perpendicular to the direction of the beams, consist exclusively of four rectangular patches, preferably all identical, associated with the lateral beams , two of these pellets being below these respective beams and the other two pellets above these same beams, the length and the width of each patch being chosen as a function of the respective values of the coma defects in vertical and horizontal direction to correct.
  • the fault correction is carried out in a particularly simple manner. Furthermore, the correction means (or method) is easily adapted. ble from one type of tube to another because the length of each rectangular element is a direct function of the height of the coma defect to be corrected and, similarly, the width of each element is a direct function of the magnitude of the defect of coma in horizontal direction.
  • the sensitivity of the horizontal scanning is increased because, with the magnetic correction elements of the invention, the magnetic field of horizontal deflection is increased in particular for the lateral beams while the correction elements known up to now decrease the sensitivity of the horizontal scanning, that is to say require a higher power supply of the deflectors.
  • the color television tube 10 is of the type with a perforated mask 11 placed inside the tube in front of the screen 12 and with electron guns 13 producing three beams 14, 15 and 16 coplanar.
  • the central beam 14 is, in this example, that which is intended to excite the green phosphorus on the screen while the lateral beams 15 and 16 excite the blue and red phosphors respectively.
  • the displacement of these beams, in order to scan the screen 12, is carried out by supplying coils 17 of horizontal and vertical deflection which produce magnetic fields allowing the displacement of the three beams 14, 15, 16 respectively in horizontal and vertical directions.
  • the barrels 13 are arranged at the rear of the tube in the cylindrical part 18 called the neck.
  • the deflection coils 17 are arranged partly around the neck 18 and partly around the flared section 19 connecting the neck 18 to the slab 20 presenting the screen 12.
  • the deflector 17 is such that it practically ensures self-convergence, that is to say the convergence of the three beams 14, 15, 16 over the entire screen. However, there still remains the coma defect which is reflected on the screen (FIG. 2) by different dimensions of the images produced by the three beams.
  • the green central beam V 14 produces a rectangular image 21 while the blue lateral beams B and red R produce an image 22, also rectangular, narrower and higher than the image 21.
  • the vertical sides of the image 22 are therefore between the vertical sides of image 21, the distance between two adjacent vertical sides of images 21 and 22 being, in the example (tube whose screen diagonal measures 51 cm), of the order of 0 , 3 mm and the horizontal sides of image 21 are between the horizontal sides of image 22, the distance h between two neighboring horizontal sides in the example being of the order of 0.8 mm.
  • the magnetic field at the rear of the deflector 17 is modified, that is to say on the side of the barrels 13.
  • pellets or plates with high magnetic permeability are used which are supported by the last electrode 23 (FIGS. 3 and 4) of the barrels, that is to say the electrode facing the screen 12.
  • This electrode 23 has a cup shape with a cylindrical edge 25 and bottom 24 perpendicular to the axis 26 of the tube. This bottom is pierced with three holes or openings of coplanar axes lying in a plane passing through the horizontal axis of the screen.
  • the central hole 27 is intended to allow the green beam 14 to pass through while the lateral holes 28 and 29 allow the blue 15 and red beams to pass through 16.
  • the magnetic elements are welded to the bottom 24 of the cup 23. They consist of plates made of an iron-nickel alloy.
  • four rectangular plates 30, 31, 32, 33 are provided (made of an "hyster" at 48% nickel) above and below the openings 28 and 29.
  • the rectangular plate 30 is above the opening 28 with its large side 30, horizontal, the middle of this large side 30, being at the right of the axis of the hole 28 intended to allow the excitation beam of the blue phosphors to pass.
  • the perpendicular bisector on the side 30 passes through the center of the hole 28.
  • the plate 31 is below the hole 28, in a position symmetrical with the plate 30 relative to the center of the hole 18.
  • the plate 32 is disposed relative to the hole 29, like the plate 30 relative to the hole 28.
  • the plate 33 is arranged relative to the hole 29 like the plate 31 relative to the hole 28.
  • the axis of the hole 27 is 5.1 mm away from the axis of the hole 28 or 29 and the thickness of the plates is 0.25 mm.
  • the lines 40 of the vertical deflection magnetic field Vx are spaced from one another around the holes 28 and 29.
  • the vertical deflection magnetic field is therefore attenuated for the blue-red image.
  • the lines of vertical deflection field 41 are, around the hole 27, close to one another: the magnetic field of vertical deflection is therefore increased for the beam 14 of excitation of the green. So we get the correction in the chosen direction: increase of the vertical deviation for green and decrease of the vertical deviation for blue and red.
  • FIG. 5 also shows that the field lines 42 of horizontal deflection Hy are brought closer to each other around the holes 28 and 29. These lines of field of horizontal deflection are also brought closer to each other around the hole 27, but in a lesser extent.
  • the horizontal deflection magnetic field is therefore increased for the three excitation beams, but it is more increased for the blue and red phosphors than for the green.
  • the desired result is also obtained, that is to say a relative reduction in the horizontal deviation for green compared to the horizontal deviation for blue and red.
  • the curves 45, 46 and 47 are curves of variation of the horizontal defect d of coma as a function of the dimension A for three dimensions L, of values L o , L 1 and L 2 respectively .
  • Curves 48, 49 and 50 are similar to curves 45, 46 and 47 respectively, but for the defect h of vertical coma.
  • the plates according to the invention make it possible to reduce the power supply energy of the coils of horizontal deflection. In other words, unlike previous embodiments, the correction is not carried out to the detriment of the horizontal scanning sensitivity.
  • the long side of the plates 30 to 33 is horizontal, it should be noted that, as a variant, these long sides may have other directions, that is to say be oblique to the 'horizontal. In addition, these long sides are not necessarily all parallel to each other.
  • the elements 30 to 33 are simple plates without extension along the axis 26.

Landscapes

  • Video Image Reproduction Devices For Color Tv Systems (AREA)
  • Color Television Image Signal Generators (AREA)
  • Testing, Inspecting, Measuring Of Stereoscopic Televisions And Televisions (AREA)
  • Picture Signal Circuits (AREA)

Claims (7)

1. Farbfernsehröhre vom autokonvergenten Typ, mit drei coplanaren Elektronenstrahlen (14, 15, 16), mit magnetischen Coma-Fehlerkorrekturelementen hinter der Ablenkeinheit (17), dadurch gekennzeichnet, dass bei Coma-Fehlern kleiner Grösse in der Grössenordnung von 1 mm oder weniger in jeder Richtung und von entgegengesetztem Sinn in Horizontalrichtung und Vertikalrichtung die Korrekturelemente ausschliesslich durch vier Plättchen (30, 31, 32, 33) von rechtwinkliger Form gebildet sind, deren Ebene senkrecht zur Achse (26) der Röhre liegt, wobei diese Plättchen oberhalb und unterhalb jedes der seitlichen Strahlen (15, 16) angeordnet sind, wobei die Mitte jeder Seite jedes Plättchens in der Senkrechten des entsprechenden seitlichen Strahls liegt; wobei weiterhin eine Abmessung (A) jedes Plättchens die Grösse der Korrektur in einer Richtung und die andere Abmessung (L) die Coma-Korrektur in der anderen Richtung beeinflusst.
2. Röhre nach Anspruch 1, dadurch gekennzeichnet, dass der Coma-Fehler dergestalt ist, dass das durch den zentralen Strahl erzeugte Bild (21 ) breiter und von geringerer Höhe als das Bild (22) ist, welches durch die seitlichen Strahlen erzeugt wird, wobei die rechtwinkligen Plättchen ihre grosse Abmessung (A) in Horizontalrichtung aufweisen.
3. Röhre nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die Plättchen (30, 31, 32, 33) untereinander völlig gleich sind.
4. Röhre nach Anspruch 2, dadurch gekennzeichnet, dass der horizontale Coma- Fehler in der Grössenordnung von 0,3 mm liegt und der vertikale Coma-Fehler in der Grössenordnung von 0,8 mm liegt, wobei die Horizontalabmessung eines Plättchens in der Grössenordnung von 4,5 mm und seine Vertikalabmessung in der Grössenordnung von 1,25 mm liegt, wobei der Abstand zwischen zwei benachbarten Strahlen vor ihrer Ablenkung in der Grössenordnung von 5,1 mm liegt.
5. Röhre nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, dass die Plättchen in an sich bekannter Weise fest mit der letzten Elektrode (23) der Elektronenkanonen (13) verbunden sind.
6. Röhre nach Anspruch 1, dadurch gekennzeichnet, dass die rechtwinkligen Plättchen ihre grösseren Abmessungen schräg zur Horizontalrichtung aufweisen.
7. Röhre nach Anspruch 6, dadurch gekennzeichnet, dass die grösseren Abmessungen der rechtwinkligen Plättchen nicht untereinander parallel sind.
EP84400706A 1983-04-18 1984-04-10 Farbfernsehröhre mit einer Korrektur von Komafehlern geringer Amplitude Expired EP0125949B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84400706T ATE28012T1 (de) 1983-04-18 1984-04-10 Farbfernsehroehre mit einer korrektur von komafehlern geringer amplitude.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8306312A FR2544548B1 (fr) 1983-04-18 1983-04-18 Tube de television en couleurs a correction de defauts de coma de faible amplitude
FR8306312 1983-04-18

Publications (2)

Publication Number Publication Date
EP0125949A1 EP0125949A1 (de) 1984-11-21
EP0125949B1 true EP0125949B1 (de) 1987-06-24

Family

ID=9287970

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84400706A Expired EP0125949B1 (de) 1983-04-18 1984-04-10 Farbfernsehröhre mit einer Korrektur von Komafehlern geringer Amplitude

Country Status (7)

Country Link
US (1) US4725757A (de)
EP (1) EP0125949B1 (de)
JP (1) JPH077643B2 (de)
AT (1) ATE28012T1 (de)
DE (1) DE3464438D1 (de)
FR (1) FR2544548B1 (de)
HK (1) HK27090A (de)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3665111D1 (en) * 1985-09-27 1989-09-21 Hitachi Ltd Convergence correcting device capable of coma correction for use in a cathode ray tube having in-line electron guns
JP2661024B2 (ja) * 1986-12-27 1997-10-08 ソニー株式会社 陰極線管
FR2818799A1 (fr) * 2000-12-22 2002-06-28 Thomson Tubes & Displays Systeme de deflexion pour tube a rayons cathodiques couleur corrige en coma horizontale
CN1261966C (zh) 2002-10-02 2006-06-28 Lg飞利浦显示器(韩国)株式会社 彩色阴极射线管及电子枪

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4142131A (en) * 1975-11-12 1979-02-27 Hitachi, Ltd. Color picture tube
JPS5845135B2 (ja) * 1975-11-12 1983-10-07 株式会社日立製作所 ヘンコウジカイセイギヨソシツキカラ−ジユゾウカン
US4225804A (en) * 1978-04-22 1980-09-30 Gte Sylvania N.V. Cathode ray tube coma correction device
US4457733A (en) * 1980-09-29 1984-07-03 Zenith Radio Corporation Method for providing coextensive raster patterns in television CRT in-line electron guns
JPS5780640A (en) * 1980-11-07 1982-05-20 Toshiba Corp Color picture tube unit
US4370593A (en) * 1980-12-30 1983-01-25 Rca Corporation In-line electron gun and method for modifying the same
JPS57126047A (en) * 1981-01-30 1982-08-05 Hitachi Ltd Color cathode-ray tube
JPS57187844A (en) * 1981-05-15 1982-11-18 Toshiba Corp Magnetic focusing crt
DE3126344A1 (de) * 1981-07-03 1983-02-24 Anton Dr. 7900 Ulm Casel Ablenkeinheit fuer eine dreistrahlige farbfernseh-bildroehre

Also Published As

Publication number Publication date
JPS59198641A (ja) 1984-11-10
FR2544548A1 (fr) 1984-10-19
FR2544548B1 (fr) 1985-12-27
HK27090A (en) 1990-04-12
JPH077643B2 (ja) 1995-01-30
US4725757A (en) 1988-02-16
EP0125949A1 (de) 1984-11-21
ATE28012T1 (de) 1987-07-15
DE3464438D1 (en) 1987-07-30

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