EP0164771B1 - Image tube - Google Patents

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Publication number
EP0164771B1
EP0164771B1 EP85200640A EP85200640A EP0164771B1 EP 0164771 B1 EP0164771 B1 EP 0164771B1 EP 85200640 A EP85200640 A EP 85200640A EP 85200640 A EP85200640 A EP 85200640A EP 0164771 B1 EP0164771 B1 EP 0164771B1
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EP
European Patent Office
Prior art keywords
deflection
field
electron beam
plates
display tube
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
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EP85200640A
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German (de)
French (fr)
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EP0164771A1 (en
Inventor
Jan Gerritsen
Otto Mensies
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Koninklijke Philips NV
Original Assignee
Philips Gloeilampenfabrieken NV
Koninklijke Philips Electronics NV
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Publication of EP0164771A1 publication Critical patent/EP0164771A1/en
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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
    • H01J29/48—Electron guns
    • H01J29/51—Arrangements for controlling convergence of a plurality of beams by means of electric field only
    • 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

Definitions

  • the invention relates to an image display tube with an evacuated piston, which consists of an image window, a cone and a neck, in which an electron beam generator for generating an electron beam is received, which on a screen, which is attached to the inside of the image window, to an impact leak focused and deflected on this screen in two essentially mutually perpendicular deflection directions by pillow-shaped deflection fields of a deflection coil system.
  • Such a picture display tube is used, for example, in an arrangement for representing symbols and / or figures which, for. B. generated by a computer.
  • Such a picture display tube is known, for example, from the "Philips Data Handbook", Electron Tubes, Part 8, July 1983, Monitor Tubes.
  • deflection coils are used in which the generated horizontal deflection field, but also mostly the vertical deflection field, is designed in a pillow-like manner to minimize the raster distortion.
  • Such pillow-shaped deflection fields are known to influence the shape of the electron beam and thus, on the screen, the shape of the impact leak that this beam forms. It is now very desirable for data graphics tubes that the impact leak does not fluctuate too much across the entire screen, so that symbols and figures in the center, in the corners and on the edge of the screen are displayed almost equally sharply.
  • field shapers to reduce deflection defocusing (see, for example, US Pat. No. 4,346,327).
  • the invention has for its object to provide structurally simple and easy to arrange field formers for a picture display tube of the type mentioned.
  • edge fields of the deflection fields on the beam generator side of the deflection coil system contain, by means of field shapers, four flat plates made of ferromagnetic material which extend essentially from the electron beam in the deflection directions and which extend around the electron beam are arranged at a substantially equal distance from this beam generator end, are deformed to barrel shape.
  • the sometimes barrel-shaped distortion of the deflection fields means that the impact leakage distortion at the edge, but especially in the corners of the screen, is significantly reduced.
  • the field formers can easily be cut from ferromagnetic sheet metal and attached to the centering plate at the end of the beam generator. In addition, it was found that such field formers can result in an increase in the sensitivity to deflection.
  • the barrel-shaped distortion of the field becomes even clearer, but there is almost no increase in sensitivity to distraction.
  • the field formers for the horizontal deflection field preferably extend from the beam generator over a greater distance along the electron beam than the field formers for the vertical deflection field. This is particularly the case with so-called “hybrid” deflection coils (deflection coils both with saddle and with toroid coils).
  • the plates extending from the electron beam in the deflection directions are preferably provided with gaps extending in the deflection directions to prevent eddy currents in the field formers.
  • the additional plates made of ferromagnetic material can also be provided with slots. These slots are particularly important in field formers or in parts of field formers that extend essentially perpendicular to the horizontal field, because this deflection field fluctuates with the highest frequencies; (Horizontal frequency).
  • an image display tube of the type mentioned at the beginning shows the edge areas of the pillow-shaped deflection areas the beam generator side can be made barrel-shaped using four field formers.
  • the field formers shown in EP-A-112 567 do not contain four substantially flat plates extending substantially from the electron beam in the deflection directions, nor are they attached at a substantially equal distance from the end of the beam generator.
  • the plates of the field formers according to the invention are essentially flat, i. H. that they are simple flat sheets or folded sheets against themselves.
  • FIG. 1 shows a partially broken perspective view of an image display tube according to the invention.
  • This tube contains a glass bulb 1, which consists of an image window 2, a cone 3 and a neck 4, in which an electron beam generator 5 for generating an electron beam 6 is received.
  • This electron beam 6 is focused on a screen 7 to an impact spot 8.
  • the screen 7 is attached to the inside of the picture window 2.
  • the electron beam is deflected on the screen 7 in two mutually perpendicular directions x and y with the aid of the deflection coil system 9.
  • the deflection fields are designed in the form of a pillow to connect raster distortion of the raster described with the electron beam 6 on the screen 7 or to greatly reduce this raster distortion.
  • the deflection defocusing caused thereby can be reduced with field shapers according to FIG. 2.
  • These field formers are attached to the end 10 of the beam generator 5 which faces the deflection coil system 9.
  • the display tube is equipped with a base 11 with connection pins 12.
  • Fig. 2 is a perspective view of the beam generator 5 of the display tube of Fig. 1.
  • This beam generator includes a control grating (G-1) 20, a second grating (G-2) 21 and a focusing lens made up of electrodes 22, 23 and 24 exists (G - 3, G - 4 or G - 5).
  • the cathode which is not visible here, is located in the control grid.
  • the voltages to the electrodes are shown in the figure.
  • a centering plate 26 provided with an opening 25 is attached to the electrode 24. Centering springs are attached to this plate for centering the jet generator in the tube neck, but are omitted in this figure.
  • the edge field of the pillow-shaped deflection fields of the deflection coil system 9 see FIG.
  • dx and dy are the impact leak dimensions in mm in the center of the screen, on the top and bottom (N / S), on the left and right side (E / W) and in the corners of the screen.
  • the average magnification of the impact leak dimensions (in%), in particular in the corners of the screen, is significantly reduced.
  • the impact leak dimensions apply to an electron beam current of approximately 100 uA in a picture display tube with a picture diagonal of 31 cm and a 90 'deflection of the electron beam.
  • field shapers 27 and 29 it is possible to make a set of field shapers, for example field shapers 27 and 29, longer (for example 14 mm) than field shapers 28 and 30. This will move the left and right sides of the Screen (O / W) the average magnification of the impact leak is also reduced compared to the previous table.
  • FIG. 3 shows the barrel-shaped distortion of a pillow-shaped horizontal deflection field, of which some field lines 40 of the field formers 27, 28, 29 and 30 are shown.
  • FIG. 5 shows the magnetic field strength B, divided by the supplied field strength B ext , as a percentage depending on the distance from the axis 32 of the beam generator 5 in the direction of the field 40 according to FIG. 3.
  • FIG. 6 shows the barrel distortion of a pillow-shaped horizontal deflection field, of which some field lines 50 are shown, by T-shaped field formers 127, 128, 129, 130.
  • T-shaped field formers 127, 128, 129, 130 At the ends 51 of the plates facing away from the electron beam 6, which extend away from the electron beam, additional plates 52 and 53 made of ferromagnetic material are attached, which extend essentially perpendicular to the field to be formed.
  • the plates 52 extend almost perpendicular to the horizontal field shown and the plates 53 almost perpendicular to the vertical field, not shown.
  • FIGS. 7 and 8 are analogous to FIGS. 4 and 5.
  • the standardized field strength is approximately 100%.
  • the field is designed with the field formers according to FIG. 3 with a clear barrel shape. There is no increase in sensitivity to distraction.
  • FIG. 9 shows a cross section through a T-shaped field former 60, which is made from a piece of sheet metal.
  • the radius of curvature of the end 61 should be chosen to be as small as possible for the best possible barrel-shaped field.

Landscapes

  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)
  • Details Of Television Scanning (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)

Description

Die Erfindung betrifft eine Bildwiedergaberöhre mit einem evakuierten Kolben, der aus einem Bildfenster, einem Konus und einem Hals besteht, in den ein Elektronenstrahlerzeuger zum Erzeugen eines Elektronenstrahls aufgenommen ist, der auf einem Bildschirm, der an der Innenseite des Bildfensters angebracht ist, zu einem Auftreffleck fokussiert und über diesen Bildschirm in zwei im wesentlichen zueinander senkrecht verlaufenden Ablenkrichtungen durch kissenförmige Ablenkfelder eines Ablenkspulensystems abgelenkt wird.The invention relates to an image display tube with an evacuated piston, which consists of an image window, a cone and a neck, in which an electron beam generator for generating an electron beam is received, which on a screen, which is attached to the inside of the image window, to an impact leak focused and deflected on this screen in two essentially mutually perpendicular deflection directions by pillow-shaped deflection fields of a deflection coil system.

Eine derartige Bildwiedergaberöhre wird beispielsweise in einer Anordnung zum Darstellen von Symbolen und/oder Figuren verwendet, die z. B. von einem Computer erzeugt werden. Eine derartige Bildwiedergaberöhre wird auch mit Daten-Graphik-Röhre bezeichnet (DGD = Data Graphic Display).Such a picture display tube is used, for example, in an arrangement for representing symbols and / or figures which, for. B. generated by a computer. Such a picture display tube is also referred to as a data graphics tube (DGD = Data Graphic Display).

Eine derartige Bildwiedergaberöhre ist beispielsweise aus dem "Philips Data Handbook", Electron Tubes, Teil 8, Juli 1983, Monitor Tubes, bekannt.Such a picture display tube is known, for example, from the "Philips Data Handbook", Electron Tubes, Part 8, July 1983, Monitor Tubes.

Bei derartigen Bildwiedergaberöhren werden Ablenkspulen verwendet bei denen das erzeugte Horizontalablenkfeld, aber auch meistens das Vertikalablenkfeld, zur Minimierung der Rasterverzeichnung kissenförmig gestaltet ist. Derartige kissenförmige Ablenkfelder beeinflussen jedoch bekanntlich die Form des Elektronenstrahls und also auf dem Bildschirm die Form des Auftrefflecks, den dieser Strahl bildet. Es ist nunmehr bei Datengraphikröhren sehr erwünscht, dass der Auftreffleck über den ganzen Bildschirm nicht zu stark schwankende Abmessungen hat, so dass Symbole und Figuren in der Mitte, in den Ecken und am Rande des Bildschirmes nahezu gleich scharf dargestellt werden. Nun ist bei Farbbildwiedergaberöhren bekannt, zur Reduzierung von Ablenkdefokussierung Feldformer zu benutzen (siehe beispielsweise US-PS-4 346 327).In such picture display tubes deflection coils are used in which the generated horizontal deflection field, but also mostly the vertical deflection field, is designed in a pillow-like manner to minimize the raster distortion. Such pillow-shaped deflection fields, however, are known to influence the shape of the electron beam and thus, on the screen, the shape of the impact leak that this beam forms. It is now very desirable for data graphics tubes that the impact leak does not fluctuate too much across the entire screen, so that symbols and figures in the center, in the corners and on the edge of the screen are displayed almost equally sharply. It is now known for color image display tubes to use field shapers to reduce deflection defocusing (see, for example, US Pat. No. 4,346,327).

Der Erfindung liegt die Aufgabe zugrunde, baulich einfache und auf einfache Weise anzuordnende Feldformer für eine Bildwiedergaberöhre der eingangs erwähnten Art zu schaffen.The invention has for its object to provide structurally simple and easy to arrange field formers for a picture display tube of the type mentioned.

Diese Aufgabe wird mit einer erfindungsgemässen Bildwiedergaberöhre eingangs erwähnter Art dadurch gelöst, dass die Randfelder der Ablenkfelder an der Strahlerzeugerseite des Ablenkspulensystems durch Feldformer, die vier um den Elektronenstrahl gruppierte, vom Elektronenstrahl sich im wesentlichen in den Ablenkrichtungen wegerstreckenden im wesentlichen ebene Platten aus Ferromagnetmaterial enthalten und in einem im wesentlichen gleichen Abstand von diesem Strahlerzeugerende angeordnet sind, auf Tonnenform deformiert werden.This object is achieved with an image display tube according to the invention of the type mentioned at the outset in that the edge fields of the deflection fields on the beam generator side of the deflection coil system contain, by means of field shapers, four flat plates made of ferromagnetic material which extend essentially from the electron beam in the deflection directions and which extend around the electron beam are arranged at a substantially equal distance from this beam generator end, are deformed to barrel shape.

Die stellenweise tonnenförmige Verzeichnung der Ablenkfelder hat zur Folge, dass die Auftreffleckverzerrung am Rande, aber besonders in den Ecken des Bildschirmes wesentlich reduziert wird. Die Feldformer können auf einfache Weise aus Ferromagnetblech geschnitten und auf der Zentrierplatte am Strahlerzeugerende befestigt werden. Ausserdem wurde gefunden, dass derartige Feldformer eine Vergrösserung der Ablenkempfindlichkeit zur Folge haben können.The sometimes barrel-shaped distortion of the deflection fields means that the impact leakage distortion at the edge, but especially in the corners of the screen, is significantly reduced. The field formers can easily be cut from ferromagnetic sheet metal and attached to the centering plate at the end of the beam generator. In addition, it was found that such field formers can result in an increase in the sensitivity to deflection.

Wenn sich an den vom Elektronenstrahl abgewandten Enden von zumindest zwei der Platten, die in der Verlängerung in einer Ablenkrichtung liegen, zusätzliche Platten aus Ferromagnetmaterial befinden, die sich im wesentlichen senkrecht zum zu bildenden Feld erstrecken, tritt die tonnenförmige Verzeichnung des Feldes noch deutlicher hervor, aber es gibt nahezu keine Vergrösserung der Ablenkempfindlichkeit. Da sich das horizontale Ablenkfeld bei vielen Spulenarten weniger weit zum Elektronenstrahlerzeuger als im Vertikalablenkfeld erstreckt, erstrecken sich die Feldformer für das Horizontalablenkfeld vorzugsweise vom Strahlerzeuger über einen grösseren Abstand entlang des Elektronenstrahls als die Feldformer für das Vertikalablenkfeld. Dies ist insbesondere der Fall bei sog. "Hybrid"-Ablenkspulen (Ablenkspulen sowohl mit Sattel - als auch mit Toroidspulen).If at the ends of at least two of the plates facing away from the electron beam, which are located in the extension in a deflection direction, there are additional plates made of ferromagnetic material which extend essentially perpendicular to the field to be formed, the barrel-shaped distortion of the field becomes even clearer, but there is almost no increase in sensitivity to distraction. Since in many types of coils the horizontal deflection field extends less far from the electron beam generator than in the vertical deflection field, the field formers for the horizontal deflection field preferably extend from the beam generator over a greater distance along the electron beam than the field formers for the vertical deflection field. This is particularly the case with so-called "hybrid" deflection coils (deflection coils both with saddle and with toroid coils).

Die sich vom Elektronenstrahl in den Ablenkrichtungen erstreckenden Platten sind vorzugsweise mit sich in den Ablenkrichtungen erstreckenden Spalten zur Verhinderung von Wirbelströmen in den Feldformern versehen. Dazu können auch die Zusatzplatten aus Ferromagnetmaterial mit Schlitzen versehen sein. Diese Schlitze sind insbesondere in Feldformern oder in Teilen von Feldformern wichtig, die sich im wesentlichen senkrecht zum Horizontalfeld erstrecken, weil dieses Ablenkfeld mit den höchsten Frequenzen schwankt; (Horizontalfrequenz).The plates extending from the electron beam in the deflection directions are preferably provided with gaps extending in the deflection directions to prevent eddy currents in the field formers. For this purpose, the additional plates made of ferromagnetic material can also be provided with slots. These slots are particularly important in field formers or in parts of field formers that extend essentially perpendicular to the horizontal field, because this deflection field fluctuates with the highest frequencies; (Horizontal frequency).

Es sei bemerkt dass die ältere europäische Patentanmeldung EP-A-112 567 die für die Vertragsstaaten Deutschland und Grossbritannien zu dem Stande der Technik gehört (Artikel 54 (3) EPÜ), ein Bildwiedergaberöhre eingangs erwähnten Art zeichnet in den die Randfelder der kissenförmigen Ablenkfelder an der Strahlenerzeugerseite mittels vier Feldformer tonnenförmig gestaltet werden. Die in EP-A-112 567 gezeichnete Feldformer enthalten jedoch nicht vier sich vom Elektronenstrahl im wesentlichen in den Ablenkrichtungen wegerstreckende im wesentlichen ebene Platten, noch sind sie in einem im wesentlichen gleichen Abstand vom Strahlerzeugerende befestigt. Die Platten der erfindungsgemässen Feldformer sind in wesentlichen eben, d. h. dass es einfache ebene Platten oder gegen sich selbst gefaltze ebene Platten sind.It should be noted that the older European patent application EP-A-112 567, which belongs to the state of the art for the contracting states of Germany and Great Britain (Article 54 (3) EPC), an image display tube of the type mentioned at the beginning shows the edge areas of the pillow-shaped deflection areas the beam generator side can be made barrel-shaped using four field formers. However, the field formers shown in EP-A-112 567 do not contain four substantially flat plates extending substantially from the electron beam in the deflection directions, nor are they attached at a substantially equal distance from the end of the beam generator. The plates of the field formers according to the invention are essentially flat, i. H. that they are simple flat sheets or folded sheets against themselves.

Ausführungsbeispiele der Erfindung werden nachstehend anhand der Zeichnung näher erläutert. Es zeigen

  • Fig. 1 eine teilweise aufgebrochene perspektivische Darstellung einer erfindungsgemässen Bildwiedergaberöhre,
  • Fig. 2 eine perspektivische Darstellung eines Strahlerzeugers nach der Erfindung,
  • Fig. 3 die tonnenförmige Verzeichnung eines kissenförmigen Ablenkfeldes durch Feldformer nach der Erfindung,
  • Fig. 4 die magnetische Feldstärke B, geteilt durch die zugeführte Feldstärke Bext in Prozent, abhängig vom Abstand zur Achse des Strahlerzeugers in der Ablenkrichtung des Feldes nach Fig. 3, und
  • Fig. 5 dasselbe wie in Fig. 4, jedoch in der Richtung senkrecht zur Ablenkrichtung des Feldes nach Fig. 3,
  • Fig. 6 die tonnenförmige Verzeichnung eines kissenförmigen Ablenkfeldes durch eine andere Art erfindungsgemässer Feldformer,
  • Fig. 7 die magnetische Feldstärke B, geteilt durch die zugeführte Feldstärke Bext in Prozent, abhängig vom Abstand zur Achse des Strahlerzeugers in der Ablenkrichtung des Feldes nach Fig. 6,
  • Fig. 8 dasselbe wie in Fig. 7, jedoch in der Richtung senkrecht zur Ablenkrichtung des Feldes nach Fig. 6, und
  • Fig. 9 einen Querschnitt durch einen T-förmigen Feldformer.
Embodiments of the invention are explained in more detail below with reference to the drawing. Show it
  • 1 is a partially broken perspective view of an image display tube according to the invention,
  • 2 is a perspective view of a jet generator according to the invention,
  • 3 shows the barrel-shaped distortion of a pillow-shaped deflection field by field formers according to the invention,
  • 4 shows the magnetic field strength B divided by the supplied field strength B ext in percent, depending on the distance from the axis of the beam generator in the deflection direction of the field according to FIG. 3, and
  • 5 is the same as in FIG. 4, but in the direction perpendicular to the deflection direction of the field according to FIG. 3,
  • 6 the barrel-shaped distortion of a pillow-shaped deflection field by another type of field former according to the invention,
  • 7 shows the magnetic field strength B divided by the supplied field strength B ext in percent, depending on the distance to the axis of the beam generator in the deflection direction of the field according to FIG. 6,
  • Fig. 8 is the same as in Fig. 7, but in the direction perpendicular to the deflection direction of the field of Fig. 6, and
  • Fig. 9 shows a cross section through a T-shaped field former.

In Fig. 1 ist eine teilweise aufgebrochene, perspektivische Darstellung einer erfindungsgemässen Bildwiedergaberöhre dargestellt. Diese Röhre enthält einen Glaskolben 1, der aus einem Bildfenster 2, einem Konus 3 und einem Hals 4 besteht, in denen ein Elektronenstrahlerzeuger 5 zum Erzeugen eines Elektronenstrahls 6 aufgenommen ist. Dieser Elektronenstrahl 6 wird auf einem Bildschirm 7 zu einem Auftreffleck 8 fokussiert. Der Bildschirm 7 ist an der Innenseite des Bildfensters 2 angebracht. Der Elektronenstrahl wird über den Bildschirm 7 in zwei zueinander senkrecht verlaufenden Richtungen x und y mit Hilfe des Ablenkspulensystems 9 abgelenkt. Zur Verbinderung von Rasterverzeichnung des mit dem Elektronenstrahl 6 auf dem Bildschirm 7 beschriebenen Rasters oder zum starken Herabsetzen dieser Rasterverzeichnung sind die Ablenkfelder kissenförmig gestaltet. Die dadurch verursachte Ablenkdefokussierung kann mit Feldformern gemäss Fig. 2 reduziert werden. Diese Feldformer sind am Ende 10 des Strahlerzeugers 5 angebracht, der dem Ablenkspulensystem 9 zugewandt ist. Die Wiedergaberöhre ist mit einem Sockel 11 mit Anschlusstiften 12 ausgerüstet.1 shows a partially broken perspective view of an image display tube according to the invention. This tube contains a glass bulb 1, which consists of an image window 2, a cone 3 and a neck 4, in which an electron beam generator 5 for generating an electron beam 6 is received. This electron beam 6 is focused on a screen 7 to an impact spot 8. The screen 7 is attached to the inside of the picture window 2. The electron beam is deflected on the screen 7 in two mutually perpendicular directions x and y with the aid of the deflection coil system 9. The deflection fields are designed in the form of a pillow to connect raster distortion of the raster described with the electron beam 6 on the screen 7 or to greatly reduce this raster distortion. The deflection defocusing caused thereby can be reduced with field shapers according to FIG. 2. These field formers are attached to the end 10 of the beam generator 5 which faces the deflection coil system 9. The display tube is equipped with a base 11 with connection pins 12.

Fig. 2 ist eine perspektivische Darstellung des Strahlerzeugers 5 der Wiedergaberöhre nach Fig. 1. Dieser Strahlerzeuger enthält ein Steuergitter (G - 1) 20, ein zweites Gitter (G - 2) 21 und eine Fokussierungslinse, die aus den Elektroden 22, 23 und 24 besteht (G - 3, G - 4 bzw. G - 5). Im Steuergitter befindet sich die hier nicht sichtbare Kathode. Die Spannungen zu den Elektroden sind in der Figur angegeben. An der Elektrode 24 ist eine mit einer Öffnung 25 versehene Zentrierplatte 26 befestigt. Zum Zentrieren des Strahlerzeugers im Röhrenhals sind an dieser Platte Zentrierfedern befestigt, die jedoch in dieser Figur weggelassen sind. Das Randfeld der kissenförmigen Ablenkfelder des Ablenkspulensystems 9 (siehe Fig. 1) wird von Feldformern 27, 28, 29 und 30 tonnenförmig gestaltet, wie weiter unten anhand der folgenden Figuren erläutert wird. In den senkrecht zum Horizontalfeld verlaufenden Feldformern 28 und 30 sind Schlitze 31 zur Reduzierung des Auftretens von Wirbelströmen angebracht. Es ist selbstverständlich möglich, auch die Feldformer 27 und 29 mit derartigen Schlitzen zu versehen. Die Feldformer haben beispielsweise eine Länge von 10 mm in Richtung auf die Elektronenstrahlerzeugerachse 32; ihre Breite beträgt z. B. 4,8 mm und die Dicke 0,25 mm. Die Feldformer können aus NiFe-Blech (mit 48 % Ni) geschnitten und mittels Punktschweissen an der Zentrierplatte 26 befestigt werden.Fig. 2 is a perspective view of the beam generator 5 of the display tube of Fig. 1. This beam generator includes a control grating (G-1) 20, a second grating (G-2) 21 and a focusing lens made up of electrodes 22, 23 and 24 exists (G - 3, G - 4 or G - 5). The cathode, which is not visible here, is located in the control grid. The voltages to the electrodes are shown in the figure. A centering plate 26 provided with an opening 25 is attached to the electrode 24. Centering springs are attached to this plate for centering the jet generator in the tube neck, but are omitted in this figure. The edge field of the pillow-shaped deflection fields of the deflection coil system 9 (see FIG. 1) is made barrel-shaped by field shapers 27, 28, 29 and 30, as will be explained further below with reference to the following figures. Slots 31 for reducing the occurrence of eddy currents are provided in the field formers 28 and 30 running perpendicular to the horizontal field. Of course, it is also possible to provide the field formers 27 and 29 with such slots. The field formers have, for example, a length of 10 mm in the direction of the electron gun axis 32; its width is z. B. 4.8 mm and the thickness 0.25 mm. The field formers can be cut from NiFe sheet (with 48% Ni) and attached to the centering plate 26 by means of spot welding.

Mit dem beschriebenen Strahlerzeuger werden die in nachstehender Tabelle angegebenen Ergebnisse erhalten:

Figure imgb0001
dx und dy sind die Auftreffleckabmessungen in mm im Zentrum des Bildschirmes, an der Ober- und Unterseite (N/S), an der linken und rechten Seite (O/W) und in den Ecken des Bildschirmes. Mit Hilfe der Erfindung wird die mittlere Vergrösserung der Auftreffleckabmessungen (in %) insbesondere in den Ecken des Bildschirmes wesentlich reduziert. Die Auftreffleckabmessungen gelten für einen Elektronenstrahlstrom von etwa 100 uA in einer Bildwiedergaberöhre mit einer Bilddiagonale von 31 cm und einer 90`-Ablenkung des Elektronenstrahls.With the jet generator described, the results given in the table below are obtained:
Figure imgb0001
 dx and dy are the impact leak dimensions in mm in the center of the screen, on the top and bottom (N / S), on the left and right side (E / W) and in the corners of the screen. With the help of the invention, the average magnification of the impact leak dimensions (in%), in particular in the corners of the screen, is significantly reduced. The impact leak dimensions apply to an electron beam current of approximately 100 uA in a picture display tube with a picture diagonal of 31 cm and a 90 'deflection of the electron beam.

Es ist möglich, einen Satz von Feldformern, beispielsweise die Feldformer 27 und 29, länger (beispielsweise 14 mm) als die Feldformer 28 und 30 zu machen. Dadurch wird an der linken und rechten Seite des Bildschirmes (O/W) die mittlere Vergrösserung des Auftrefflecks zusätzlich herabgesetzt im Vergleich zur vorangehenden Tabelle.It is possible to make a set of field shapers, for example field shapers 27 and 29, longer (for example 14 mm) than field shapers 28 and 30. This will move the left and right sides of the Screen (O / W) the average magnification of the impact leak is also reduced compared to the previous table.

In Fig. 3 ist die tonnenförmige Verzeichnung eines kissenförmigen Horizontalablenkfelds dargestellt, von dem einige Feldlinien 40 der Feldformer 27, 28, 29 und 30 dargestellt sind.3 shows the barrel-shaped distortion of a pillow-shaped horizontal deflection field, of which some field lines 40 of the field formers 27, 28, 29 and 30 are shown.

In Fig. 4 ist die magnetische Feldstärke B, geteilt durch die zugeführte Feldstärke Bext in Prozent, abhängig vom Abstand zur Achse 32 des Strahlerzeugers 5 in der Ablenkrichtung des Feldes nach Fig. 3 dargestellt. Im Zentrum (x = 0) ist diese genormte Feldstärke grösser als 100 %, wodurch die Ablenkempfindlichkeit etwas ansteigt.4 shows the magnetic field strength B divided by the supplied field strength B ext in percent, depending on the distance from the axis 32 of the beam generator 5 in the deflection direction of the field according to FIG. 3. In the center (x = 0) this standardized field strength is greater than 100%, which increases the sensitivity to deflection somewhat.

In Fig. 5 ist die magnetische Feldstärke B, geteilt durch die zugeführte Feldstärke Bext, in Prozent abhängig vom Abstand zur Achse 32 des Strahlerzeugers 5 in Richtung des Feldes 40 nach Fig. 3 dargestellt.5 shows the magnetic field strength B, divided by the supplied field strength B ext , as a percentage depending on the distance from the axis 32 of the beam generator 5 in the direction of the field 40 according to FIG. 3.

In Fig. 6 ist die tonnenförmige Verzeichnung eines kissenförmigen Horizontalablenkfeldes, von dem einige Feldlinien 50 dargestellt sind, durch T-förmige Feldformer 127, 128, 129, 130 gezeigt. An den vom Elektronenstrahl 6 abgewandten Enden 51 der Platten, die sich vom Elektronenstrahl weg erstrecken, sind Zusatzplatten 52 und 53 aus Ferromagnetmaterial befestigt, die sich im wesentlichen senkrecht zu dem zu bildenden Feld erstrecken. Die Platten 52 erstrecken sich nahezu senkrecht zum dargestellten Horizontalfeld und die Platten 53 nahezu senkrecht zum nicht dargestellten Vertikalfeld.FIG. 6 shows the barrel distortion of a pillow-shaped horizontal deflection field, of which some field lines 50 are shown, by T-shaped field formers 127, 128, 129, 130. At the ends 51 of the plates facing away from the electron beam 6, which extend away from the electron beam, additional plates 52 and 53 made of ferromagnetic material are attached, which extend essentially perpendicular to the field to be formed. The plates 52 extend almost perpendicular to the horizontal field shown and the plates 53 almost perpendicular to the vertical field, not shown.

Fig. 7 und 8 sind analog den Fig. 4 und 5. Im Zentrum ist die genormte Feldstärke etwa 100 %. Das Feld wird dabei mit den Feldformern nach Fig. 3 mit deutlicher Tonnenförmigkeit gestaltet. Es tritt keine Vergrösserung der Ablenkempfindlichkeit auf.7 and 8 are analogous to FIGS. 4 and 5. In the center, the standardized field strength is approximately 100%. The field is designed with the field formers according to FIG. 3 with a clear barrel shape. There is no increase in sensitivity to distraction.

In Fig. 9 ist ein Querschnitt durch einen T-förmigen Feldformer 60 dargestellt, der aus einem Bleckstück hergestellt ist. Der Krümmungsradius des Endes 61 ist für ein möglichst gutes tonnenförmiges Feld möglichst klein zu wählen.FIG. 9 shows a cross section through a T-shaped field former 60, which is made from a piece of sheet metal. The radius of curvature of the end 61 should be chosen to be as small as possible for the best possible barrel-shaped field.

Claims (5)

1. A display tube comprising an evacuated envelope (1) consisting of a display window (2), a cone (3), and a neck (4), in which is provided an electron gun (5) for generating an electron beam (6) which is focused to form a spot (8) on a display screen (7) provided on the inside of the display window, said beam being deflected across said display screen in two substantially mutually perpendicular directions by pincushion-shaped deflection fields of a system of deflection coils (9), the edge fields of said deflection fields on the electron gun side of the system of deflection coils being deformed by means of field shapers such that they are barrel- shaped, which field shapers comprise four substantially flat plates (27 - 30) of ferromagnetic material which are arranged around the electron beam and extend away from the electron beam substantially in the directions of deflection and which are disposed at a substantially equal distance from the gun end (10).
2. A display tube as claimed in Claim 1, characterized in that at the ends of at least two of the plates remote from the electron beam, which plates are situated in line with a deflection direction, extra plates (52, 53) of a ferromagnetic material are present which extend substantially perpendicularly to the field to be shaped.
3. A display tube as claimed in Claim 1 or 2, characterized in that the field shapers for the horizontal deflection field extend from the gun over a larger distance along the electron beam than the field shapers for the vertical deflection field.
4. A display tube as claimed in any one of the preceding Claims, characterized in that at least the plates extending away from the electron beam in the deflection directions comprise slots.
5. A display tube as claimed in Claim 4, characterized in that in addition the extra plates comprise slots.
EP85200640A 1984-05-07 1985-04-24 Image tube Expired EP0164771B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL8401444 1984-05-07
NL8401444A NL8401444A (en) 1984-05-07 1984-05-07 PICTURE TUBE.

Publications (2)

Publication Number Publication Date
EP0164771A1 EP0164771A1 (en) 1985-12-18
EP0164771B1 true EP0164771B1 (en) 1989-07-12

Family

ID=19843907

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85200640A Expired EP0164771B1 (en) 1984-05-07 1985-04-24 Image tube

Country Status (9)

Country Link
US (1) US4691139A (en)
EP (1) EP0164771B1 (en)
JP (1) JPS60241630A (en)
KR (1) KR920001871B1 (en)
CA (1) CA1239975A (en)
DD (1) DD233454A5 (en)
DE (1) DE3571529D1 (en)
ES (1) ES8700498A1 (en)
NL (1) NL8401444A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2818799A1 (en) * 2000-12-22 2002-06-28 Thomson Tubes & Displays DEFLECTION SYSTEM FOR COLOR CATHODE RAY TUBE CORRECTED IN COMA HORIZONTAL

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5522907B2 (en) * 1973-05-04 1980-06-19
US3866080A (en) * 1973-08-08 1975-02-11 Rca Corp Inline electron gun having magnetically permeable plates for enhancing convergence of electron beams
JPS5615102B2 (en) * 1974-10-14 1981-04-08
JPS52123831A (en) * 1976-04-12 1977-10-18 Toshiba Corp Cothode ray tube
NL7802129A (en) * 1978-02-27 1979-08-29 Philips Nv DEVICE FOR DISPLAYING COLORED IMAGES.
JPS5583136A (en) * 1978-12-19 1980-06-23 Matsushita Electronics Corp Color image pick-up tube
JPS5738544A (en) * 1980-08-19 1982-03-03 Matsushita Electronics Corp Electromagnetic deflection system picture tube system equipment
JPS5761246A (en) * 1980-09-30 1982-04-13 Mitsubishi Electric Corp Electron gun for color picture tube
JPS5859536A (en) * 1981-10-06 1983-04-08 Toshiba Corp Color picture tube
JPS59119654A (en) * 1982-12-24 1984-07-10 Matsushita Electronics Corp Picture tube apparatus

Also Published As

Publication number Publication date
DD233454A5 (en) 1986-02-26
EP0164771A1 (en) 1985-12-18
KR850008555A (en) 1985-12-18
ES8700498A1 (en) 1986-10-01
JPS60241630A (en) 1985-11-30
CA1239975A (en) 1988-08-02
ES542824A0 (en) 1986-10-01
DE3571529D1 (en) 1989-08-17
US4691139A (en) 1987-09-01
KR920001871B1 (en) 1992-03-06
NL8401444A (en) 1985-12-02

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