EP0068182B1 - Cathode ray tube with magnetic ring - Google Patents

Cathode ray tube with magnetic ring Download PDF

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Publication number
EP0068182B1
EP0068182B1 EP82104948A EP82104948A EP0068182B1 EP 0068182 B1 EP0068182 B1 EP 0068182B1 EP 82104948 A EP82104948 A EP 82104948A EP 82104948 A EP82104948 A EP 82104948A EP 0068182 B1 EP0068182 B1 EP 0068182B1
Authority
EP
European Patent Office
Prior art keywords
magnetic ring
deflection system
tube
electrode
electron gun
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
EP82104948A
Other languages
German (de)
French (fr)
Other versions
EP0068182A1 (en
Inventor
Walter Kornaker
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.)
Nokia Deutschland GmbH
Original Assignee
Alcatel SEL AG
Standard Elektrik Lorenz AG
International Standard Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Alcatel SEL AG, Standard Elektrik Lorenz AG, International Standard Electric Corp filed Critical Alcatel SEL AG
Publication of EP0068182A1 publication Critical patent/EP0068182A1/en
Application granted granted Critical
Publication of EP0068182B1 publication Critical patent/EP0068182B1/en
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
    • H01J29/702—Convergence correction arrangements therefor
    • H01J29/703—Static convergence systems
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/48—Electron guns
    • H01J29/51—Arrangements for controlling convergence of a plurality of beams by means of electric field only

Definitions

  • the invention relates to a cathode ray tube, in particular a color picture tube, having a front screen, a conical funnel part and a rear tube neck, in which an electron gun with a focusing electrode and other electrodes for generating at least two electron beams is arranged, and a magnetic deflection system attached to the transition from the tube neck to the funnel part for deflecting the electron beams across the screen, with a magnetic ring attached to the electron gun outside the neck area covered by the deflection system.
  • the other type of electron gun has oval electrodes that are common to all three beams. Each electrode has three electron beam openings, the centers of which are all in one plane. Only the convergence pot placed at the very front in the direction of the screen has a circular cross section, as in the first type of electron gun. Tubes with such an electron gun are not yet commercially available with a magnetic ring attached to the electron gun. However, such a tube was presented at the “Electronica” exhibition in 1980, about which an article appeared in Funkschau 26/1980, page 57. In this tube, the magnetic ring was at the very front, i.e. on the side of the focusing electrode facing the screen. The deflection system was designed in such a way that it extended straight over the neck to the point where the magnetic ring was located in the front of the focusing grating.
  • the magnetic rings attached to electron guns are made of an iron-cobalt-vanadium alloy, and they can be magnetized from the outside using a strong magnetizing device to adjust the position of at least two electron beams from a cathode ray tube, particularly in the case of a color picture tube to adjust convergence, color purity and screen.
  • This magnetization initially takes place without an attached deflection system. Only then is the deflection system aligned and attached to the conical funnel part of the tube.
  • two working devices have been required for these manufacturing processes, namely a magnetizing device and a deflection system alignment device.
  • a color picture tube of the type mentioned at the outset is known from the abstract of Japanese patent application JP-A-56/15530 (Patents Abstracts of Japan, Volume 5, No. 66 (E-55) (738), 2.5.81, page 738E55).
  • the magnetic ring is attached to the outside around a focusing electrode.
  • the object of the invention is to improve a cathode ray tube of the type mentioned at the outset and to design it in such a way that the magnetizing process for the magnetic ring and the aligning process for the deflection system can be carried out quickly and safely on the simplest possible setting device.
  • a particularly favorable position of the magnetic ring, as seen in the beam direction, is approximately the center of the focusing electrode. In this position, the magnetic ring is sufficiently far away from the electrodes that generate electron beams, which are annealed during the production process of the tube. If the magnetic ring were too close to these electrodes, there would be a risk that it could also be heated to a high temperature and thus change its magnetic properties considerably. On the other hand, it would be a disadvantage if the magnetic ring were very close to the anode, which has a voltage of 25 kV.
  • the magnetic ring is in fact to be fastened in some way, which causes a deformation of the corresponding electrode at the fastening point. Such deformation, for example a notch in the direct vicinity of the anode, can lead to high voltage flashovers.
  • FIG. 1 shows a color picture tube 10 with a front screen 11, a conical funnel part 12 and a rear tube neck 13.
  • an electron gun 14 which is shown to scale in the side view according to FIG. 2.
  • a magnetic deflection system 15 is attached to the transition between the tube neck 13 and the funnel part 12. It is attached to the neck 13 by a sleeve 16 with a clamp 17.
  • the deflection system 15 is aligned during the manufacturing process of the color picture tube 10 to achieve color purity and dynamic convergence and is held in the aligned position by fastening wedges 66 made of rubber, which are pushed between the front end of the deflection system 15 and the funnel part 12.
  • the front end of the deflection system 15 is to be understood as the end facing the screen 11.
  • the terms front and back will be used throughout the description. It should be noted, however, that when the electron gun 14 is used in technical terms, the terms below and above are used instead of back and front, because the electron gun 14 is assembled and transported as an individual part in this position. In this case, the end facing the screen 11 is referred to as the upper end.
  • the electron gun 14 is shown in dashed lines in FIG. 1 and with it in a strongly dashed line a magnetic ring 19 which is attached to it.
  • the new feature of the color picture tube 10 shown in FIG. 1 is that the magnetic ring 19 is attached at a point on the electron gun 14 at which it is no longer covered by the deflection system 15 to the outside. Compared to previously known color picture tubes 10, this has been done by moving the magnetic ring 19 in the electron gun 14 further down than was previously the case.
  • a deflection system 15 can also be used, in which the sleeve 16 with the clamp 17 is shortened compared to previously known deflection systems 15. It is also possible to use a deflection system which can be attached to the front of the funnel part 12 and not to the tube neck 13 at the rear. As a result, the sleeve 16 with the clamp 17 can be omitted entirely.
  • the magnetic ring 19 is used to adjust the color purity, convergence and grid in the color picture tube 10. It consists of an iron-cobalt-vanadium alloy and is magnetized from the outside through the tube neck in such a way that the color purity, grid and convergence assume predetermined setting values . Such a setting is necessary for the majority of color picture tubes, since only very few color picture tubes go through the manufacturing process without showing any deviations in convergence, color purity and raster before a correction by a magnetic field has been carried out. However, the magnetic field generated also influences the sharpness of the electron beams, which are affected in their position. Therefore, if the position of the magnetic ring 19 on the electron gun 14 is changed, changes in the geometry of the electron gun 14 and / or the voltages applied to it must also be made.
  • FIGS. 2 to 4 An electron gun 14 is shown in FIGS. 2 to 4, to which a magnetic ring 19 can be easily attached at different points.
  • the electron gun 14 in FIG. 2 has a pressed glass plate 20 in which contact pins 21 are melted.
  • the contact pins 21 are conductively connected to contact tabs 22.
  • This is followed by a Wehnelt electrode 23, a control electrode 24, a focusing electrode 25, an anode 26 and a convergence pot 27 with contact springs 28.
  • the individual parts of the electron gun 14, that is to say the contact lug 22 and the electrodes 23 to 26, are held together by two glass rods 29 which are heated to softening in the manufacturing process and into which the opening edges 30 of the electrodes are then pressed. Only one of the two glass rods 29 can be seen in the side view.
  • the convergence pot 27 is by spot welding solution connected to the anode 26. For the sake of clarity, not all connections between contact pins 21 and contact tabs 22 are shown, and cathodes and heaters are also not shown.
  • a magnetic ring 19 is inserted into the focusing electrode 25, which is shown in dashed lines in FIGS. 1 and 2, since it cannot be seen from the outside in the side view. However, the magnetic ring 19 is shown in more detail in FIGS. 3 and 4.
  • the structure of the focusing electrode 25 is shown more clearly in the exploded view according to FIG. 3.
  • the focusing electrode 25 consists of four electrode parts 32 and an intermediate plate 33.
  • Each electrode part 32 consists of a metal pot with bottom 35, pot wall 36 and opening edge 30.
  • three beam passage openings 37 are recessed, which have a circular shape, as can be seen in the top view according to FIG. 4.
  • a central electron beam 38.1 passes through the central beam passage openings 37.1
  • an outer electron beam 38.2 passes through the outer beam passage openings 37.2.
  • the beam passage openings 37 lie next to one another in an electrode part 32, which leads to an oval configuration of the electrode part 32.
  • the electrodes 23 to 26 are only slightly narrower than the convergence pot 27.
  • the electrodes appear narrower than the convergence pot compared to the circular shape of the convergence pot 27 because of the oval embodiment shown in FIG. 4.
  • two electrode parts 32 are first put together with their bottoms 35 and connected to one another by spot welding to form a central part 39.
  • the magnetic ring 19 is then inserted into the upper electrode part 32 of this middle part 39 and fastened by means of notches 40.
  • the notches 40 are made in the pot wall 36 in such a way that they point directly above the magnetic ring 19 into the interior of the electrode part 32.
  • the intermediate plate 33 and an electrode part 32, referred to as the upper part 41, with its opening edge 30 are then placed on the upper opening edge 30 of the middle part 39.
  • the fourth electrode part 32 referred to as the lower part 42, is placed with its opening edge 30 on the lower opening edge of the central part 39. All parts are then held by the glass rods 29 pressed into the opening edges 30.
  • the shape of the magnetic ring 19 and its attachment by notches 40 can be seen in FIGS. 3 and 4.
  • the magnetic ring 19 consists of two identical magnetic ring parts 19.1, which together form an oval ring.
  • the ends of the magnet ring parts 19.1 abut one another with an air gap 43.
  • the air gaps 43 are drawn very large, so that it may appear that the ends of the magnet ring parts 19.1 are not directly adjacent to one another.
  • An electron gun 14 with the structure described has the advantage that the magnetic ring 19 can be accommodated at any point on the focusing electrode 25 without having any significant effects on the sharpness of the electron beams 38.
  • the illustrated and previously described position of the magnetic ring 19 approximately in the middle of the focusing electrode 25 is particularly advantageous. Layers on the bottom of the lower part 42 or the upper part 41 are less advantageous. If the magnetic ring 19 is inserted into the upper part 41 and fastened with notches 40, there is a risk of high-voltage flashovers between the notches 40 and the anode 26, which is at 25 kV. In the case of an electron gun 14 according to the exemplary embodiment, a voltage of approximately 7 kV is present at the focusing electrode 25.
  • electron guns 14 are also used to a large extent, in which the focusing electrode 25 is shorter and in which only about 4.5 kV are applied to it. However, this is irrelevant for the new color picture tube, since all that is important is that the magnetic ring is not covered from the outside by the deflection system 15.
  • the position of the magnet ring 19 on the bottom 35 of the lower part 42 is therefore generally of less advantage, since in the course of the production of conventional tubes 10 the cathodes (not shown) and thus the Wehnelt electrode 23 and the control electrode 24 are heated to a great extent. There is a risk that the lower part 42 and with it an inserted magnetic ring 19 will also be heated, as a result of which this would change its magnetic properties considerably. However, this danger does not exist with tubes where there is no baking out.
  • the attachment of the magnetic ring 29 in the central region of the focusing electrode 25 is of particular advantage.
  • the magnetic ring 19 can either be fastened, as shown, to the bottom 35 of the upper electrode part 32 of the middle part 39 or to the bottom of the lower electrode part 32 of the middle part 39.
  • Fastening at the top or bottom of the intermediate plate 33 can also be carried out, for which purpose tabs are expediently bent out of the edge of the intermediate plate 33 and hold the magnetic ring 19 in place.
  • Such positions and attachment options are not shown in the figures. They are also irrelevant for the new tube, since it is only a matter of the position of the magnet ring 19 in relation to the deflection system 15.
  • the magnetic ring 19 is not covered by the deflection system 15, it is also irrelevant whether it is a thin-necked color picture tube with about 29 mm outside of the neck diameter or a thick-necked tube with an outside diameter of about 36 mm or, for example, a Trinitron tube or a multi-beam oscillograph tube.
  • an electron gun 14 for a thin-necked tube is shown.
  • the magnetic ring 19 has a long inner diameter of 20.45 mm and a short inner diameter of 9.4 mm.
  • the circular convergence pot has a diameter of 27 mm.
  • the magnetic ring 19 can be attached to the inside or outside of the electron gun and it can consist of one or more magnetic ring parts. Its attachment must be adapted to the type of electrode to which it is attached. It should be noted that plate-shaped electrodes are often used instead of the cup-shaped electrodes according to the illustrated embodiment in electron guns.
  • the exact embodiment of an electron gun and the magnetic ring 19 attached to it is not significant, the exact embodiment of the deflection system is also irrelevant as long as the magnetic ring is not covered by the deflection system.
  • Deflection systems can thus be used in which both the coil pairs for the horizontal and for the vertical deflection are formed by saddle coils, and also deflection systems can be used which have toroidal and saddle coils.
  • the latter will generally be cheaper, since these combined coils can often be made shorter than deflection systems that only have saddle coils.
  • the condition that the magnetic ring is not covered by the deflection system is easier to meet.
  • the type of attachment of the deflection system is also not the main issue.
  • the particular advantage of a new cathode ray tube 10 is that all of the setting operations for the magnetic ring 19 and the deflection system 15 can be carried out in the simplest manner on a common setting device 44.
  • An adjusting device 44 is shown partially schematically in FIG. 5.
  • a carriage guide 46 for a tube receiving carriage 47 and a guide rod 48 for guiding a deflection system alignment device 49 are mounted on a device table 45.
  • the slide guide 46 and the guide rod 48 allow displacements of the tube receiving slide 47 and the deflection system alignment device 49 in the direction of the longitudinal axis 18 of the tube.
  • Deflection system alignment devices are e.g. known from US-A-3 992 578 or EP-A-0 021 275.
  • a deflection system alignment device 49 similar to the latter device is shown in partial schematic form in FIG. 5.
  • a guide slide can be displaced on the guide rod 48, to which a bearing plate 50 which is perpendicular to the longitudinal axis 18 of the tube is fastened.
  • the bearing plate 50 has a spherical cap-shaped bearing surface 51, in which a receiving ring 52 is gimbal-mounted.
  • Adjusting forces, represented by an arrow 54 act on the receiving ring 52 via a pin 53, by means of which the cardanic movement of the receiving ring 52 is carried out.
  • the adjustment mechanism is not shown for the sake of clarity. As a rule, mechanisms are available by which it is possible to operate the adjustment of the receiving ring 52 from the screen side of the setting device 44.
  • Clamping jaws 55 are adjustably attached to the receiving ring 53. These clamping jaws 55 are used to fasten a deflection system 15 in the receiving ring.
  • a deflection system 15 also shown, has a clamping ring 56 at its rear end, which is inserted into a recess in the receiving plate and is held by the adjusted clamping jaws 55.
  • the adjustment mechanism of the jaws 55 is also not shown for the sake of clarity.
  • the adjusting device 44 also has contacting devices 57, specifically an anode contacting device 57.1 and a neck contacting device 57.2.
  • the anode contact device 57.1 is mounted insulated in a device-fixed manner, but this is also not shown in detail.
  • the neck contacting device 57.2 is connected to the guide rod 48 in a non-displaceable manner via a contacting device holder 58.
  • a contacting device holder 58 At the upper end of the contact device holder 58 there is a bolt guide head 59, into which a sleeve 60 attached to the neck contact device engages.
  • the sleeve 60 is displaceably mounted in the bolt guide head 59 and is pressed forward by the force of a spring, not shown, to the screen side of the adjusting device 44 up to a contact point.
  • a magnetizing device 62 sits in front of the neck contacting device 57.2 at a distance predetermined by spacing pins 61. Such devices are e.g. described in DE-A-26 12 607 or DE-A-28 32 667. Such a magnetizing device 62 has magnetizing coils 63, which are shown schematically in dashed lines inside the magnetizing coil. The magnetizing coils 63 generally have a large number of electrical connections 64, of which only two are shown.
  • the neck contacting device 57.2 is mounted in its position in such a way that a color picture tube placed on the tube receiving carriage 47 engages with the contacting pins 21 in the adjusting device 47.2 when it is inserted into the adjusting device, thereby engaging the neck contacting device 57.2 presses slightly against the pressure of the spring in the bolt guide head 59. This counterforce ensures reliable contact and a secure fit of the color picture tube 10 in the adjusting device 44.
  • the anode contact device 57.1 is also mounted such that it just contacts the anode contact 65 attached to the funnel part 12 when the tube 10 is inserted.
  • the magnetizing device 62 is fastened to the neck contacting device 57.2 such that the tube neck 13 penetrates centrally through a recess in the magnetizing device 62 when the tube 10 engages with the contacting pins 21 in the neck contacting device 57.2.
  • the deflection system alignment device 49 holds a deflection system 15 such that a color picture tube 10 can reach with its neck 13 through the deflection system 15 unimpeded when it is inserted into the adjustment device 44.
  • the distance 67 between the deflection system alignment device 49 and the magnetization device 62 is selected such that the magnetization device 62 is just above the magnetic ring 19 when the deflection system 15 is in the correct position above the funnel part 12. In order to be able to maintain the required distance, it is advantageous if the magnetic ring is at least 5 mm behind the rear end of the deflection system.
  • the screen side of the setting device is understood below to mean the side on which the screen 11 of an inserted color picture tube 10 is located.
  • the tube receiving slide 47 with the slide guide 46 is pulled out of the adjusting device 44 all the way to the screen side.
  • the clamping jaws 55 are adjusted so that a deflection system 15 with its clamping ring 56 can be inserted into the receiving ring 52.
  • a deflection system 15 is first inserted into the receiving ring 52 and held in place by adjusting the clamping jaws 55.
  • a tube 10 is then placed on the tube receiving carriage 47 and pushed into the adjusting device 44 until the contact pins 21 engage the neck contacting device 57.2 and finally the tube 10 is held in place by engaging a not-shown notch in the receiving carriage 47.
  • the anode contact device 57.2 contacts the anode contact 65.
  • the magnet ring 19 is magnetized with the aid of the magnetizing device 62 in such a way that color purity, screen and convergence are set to predetermined values.
  • the deflection system 15 is then aligned according to predetermined setting criteria.
  • a movement of the deflection system 15 in the direction of the longitudinal axis 18 of the tube and a tilting movement with respect to the longitudinal axis of the tube is possible.
  • movements in the direction of the longitudinal axis 18 of the tube and two directions perpendicular thereto must take place for alignment.
  • the deflection system 15 After the deflection system 15 has been aligned, it is connected to the tube neck 13 via the sleeve 16 with a clamp 17 and to the funnel part 12 by means of fastening wedges 66 placed underneath.
  • Such compensation of errors that can be influenced both by the magnetic ring 19 and by the deflection system 15 can only be remedied when using a tube of the type described here, in which case the magnetic ring 19 is not covered by the deflection system 15, in which the magnetization and the alignment of the deflection system can be carried out simultaneously and independently of one another on an adjusting device of the specified type.

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Description

Die Erfindung betrifft eine Kathodenstrahlröhre, insbesondere Farbbildröhre, mit einem vorderen Bildschirm, einem konusförmigen Trichterteil und einem hinteren Röhrenhals, in dem eine Elektronenkanone mit Fokussierelektrode und anderen Elektroden zum Erzeugen mindestens zweier Elektronenstrahlen angeordnet ist, sowie einem am Übergang vom Röhrenhals zum Trichterteil angebrachten magnetischen Ablenksystem zum Ablenken der Elektronenstrahlen über den Bildschirm, mit einem an der Elektronenkanone ausserhalb des vom Ablenksystem überdeckten Halsbereichs befestigten Magnetring.The invention relates to a cathode ray tube, in particular a color picture tube, having a front screen, a conical funnel part and a rear tube neck, in which an electron gun with a focusing electrode and other electrodes for generating at least two electron beams is arranged, and a magnetic deflection system attached to the transition from the tube neck to the funnel part for deflecting the electron beams across the screen, with a magnetic ring attached to the electron gun outside the neck area covered by the deflection system.

Bisher sind zwei verschiedene Arten von Mehrstrahlelektronenkanonen mit Magnetringen bekannt geworden. Bei der einen Art von Elektronenkanonen ist für jeden von drei Elektronenstrahlen eine Einzelkanone mit jeweils einzelner Steuerelektrode, Fokussierelektrode und anderen einzelnen Elektroden vorhanden. Allen Einzelkanonen ist jedoch ein aufgesetzter, kreisrunder Konvergenztopf gemeinsam, der das dem Bildschirm zugewandte Ende der Elektronenkanone bildet. Am Boden des Konvergenztopfes ist ein kreisförmiger Magnetring eingelegt und befestigt. Röhren mit einer derartigen Elektronenkanone mit Magnetring im Konvergenztopf sind unter der Bezeichnung A 66-501 X im Handel. Diese Röhren weisen ein Ablenksystem auf, das sich weit über den Hals der Röhre erstreckt und die Elektronenkanone weitgehend abdeckt.So far, two different types of multi-beam electron guns with magnetic rings have become known. In one type of electron gun, there is a single gun for each of three electron beams, each with a single control electrode, focusing electrode and other individual electrodes. However, all the individual cannons have a circular convergence pot attached to them, which forms the end of the electron gun facing the screen. A circular magnetic ring is inserted and attached to the bottom of the convergence pot. Tubes with such an electron gun with a magnetic ring in the convergence pot are commercially available under the designation A 66-501 X. These tubes have a deflection system that extends far beyond the neck of the tube and largely covers the electron gun.

Die andere Art Elektronenkanone weist ovale Elektroden auf, die allen drei Strahlen gemeinsam sind. Jede Elektrode weist drei Elektronenstrahldurchtrittsöffnungen auf, deren Mittelpunkte alle in einer Ebene liegen. Lediglich der in Richtung Bildschirm ganz vorne aufgesetzte Konvergenztopf weist, wie bei der ersten Art von Elektronenkanone, einen kreisförmigen Querschnitt auf. Röhren mit einer solchen Elektronenkanone sind mit an der Elektronenkanone befestigtem Magnetring noch nicht im Handel. Eine solche Röhre wurde jedoch auf der Ausstellung «Electronica» 1980 vorgestellt, worüber ein Artikel in Funkschau 26/1980, Seite 57, erschien. Bei dieser Röhre war der Magnetring ganz vorne, also auf der dem Bildschirm zugewandten Seite der Fokussierelektrode angebracht. Das Ablenksystem war so beschaffen, dass es sich im ausgerichteten Zustand über den Hals gerade bis an die Stelle erstreckte, an der der Magnetring vorne im Fokussiergitter lag.The other type of electron gun has oval electrodes that are common to all three beams. Each electrode has three electron beam openings, the centers of which are all in one plane. Only the convergence pot placed at the very front in the direction of the screen has a circular cross section, as in the first type of electron gun. Tubes with such an electron gun are not yet commercially available with a magnetic ring attached to the electron gun. However, such a tube was presented at the “Electronica” exhibition in 1980, about which an article appeared in Funkschau 26/1980, page 57. In this tube, the magnetic ring was at the very front, i.e. on the side of the focusing electrode facing the screen. The deflection system was designed in such a way that it extended straight over the neck to the point where the magnetic ring was located in the front of the focusing grating.

Die an Elektronenkanonen befestigten Magnetringe bestehen aus einer Eisen-Kobalt-Vanadiumlegierung, und sie können von aussen mit einer starken Magnetisiervorrichtung zum Einstellen der Lage von mindestens zwei Elektronenstrahlen einer Kathodenstrahlröhre, insbesondere bei einer Farbbildröhre zum Einstellen von Konvergenz, Farbreinheit und Raster magnetisiert werden. Dieses Magnetisieren erfolgt zunächst ohne angebrachtes Ablenksystem. Erst danach wird das Ablenksystem ausgerichtet und am konusförmigen Trichterteil der Röhre befestigt. Für diese Fertigungsvorgänge sind bisher zwei Arbeitsvorrichtungen erforderlich, und zwar eine Magnetisiervorrichtung und eine Ablenksystemausrichtvorrichtung.The magnetic rings attached to electron guns are made of an iron-cobalt-vanadium alloy, and they can be magnetized from the outside using a strong magnetizing device to adjust the position of at least two electron beams from a cathode ray tube, particularly in the case of a color picture tube to adjust convergence, color purity and screen. This magnetization initially takes place without an attached deflection system. Only then is the deflection system aligned and attached to the conical funnel part of the tube. To date, two working devices have been required for these manufacturing processes, namely a magnetizing device and a deflection system alignment device.

Aus der Zusammenfassung der japanischen Patentanmeldung JP-A-56/15530 (Patents Abstracts of Japan, Band 5, Nr. 66 (E-55)(738), 2.5.81, Seite 738E55) ist eine Farbbildröhre der eingangs genannten Art bekannt. Bei dieser Farbbildröhre ist aussen um eine Fokussierelektrode der Magnetring angebracht.A color picture tube of the type mentioned at the outset is known from the abstract of Japanese patent application JP-A-56/15530 (Patents Abstracts of Japan, Volume 5, No. 66 (E-55) (738), 2.5.81, page 738E55). In this color picture tube, the magnetic ring is attached to the outside around a focusing electrode.

Der Erfindung liegt die Aufgabe zugrunde, eine Kathodenstrahlröhre der eingangs genannten Art zu verbessern und so auszubilden, dass der Magnetisiervorgang für den Magnetring und der Ausrichtvorgang für das Ablenksystem schnell und sicher auf einer möglichst einfachen Einstellvorrichtung durchgeführt werden können.The object of the invention is to improve a cathode ray tube of the type mentioned at the outset and to design it in such a way that the magnetizing process for the magnetic ring and the aligning process for the deflection system can be carried out quickly and safely on the simplest possible setting device.

Die Lösung dieser Aufgabe erfolgt mit den im Anspruch 1 oder 2 angegebenen Mitteln.This object is achieved with the means specified in claim 1 or 2.

Hierdurch ist es möglich, eine Einstellvorrichtung zu verwenden, bei der die Magnetisiervorrichtung direkt hinter der Ablenksystemausrichtvorrichtung in einem solchen Abstand anschliesst, dass der Magnetisiervorgang und der Ablenksystemausrichtvorgang bei gleicher Stellung der Röhre in der Einstellvorrichtung durchführbar sind. Dabei muss nur die Röhre ohne Ablenksystem, das von der Ablenksystemausrichtvorrichtung vor dem Befestigen am Trichterteil gehalten wird, in die Einstellvorrichtung eingesetzt werden, worauf das Magnetisieren und das Ausrichten des Ablenksystems in einem Arbeitsgang erfolgen kann. Dies ist von besonderem Vorteil, weil Wechselwirkungen zwischen der Lage des Ablenksystems und der einmal durch Magnetisieren des Magnetrings eingestellten Werte von Farbreinheit, Raster und Konvergenz bestehen können. Wurde nun zunächst der Magnetring zum Erzielen gewünschter Einstellwerte magnetisiert und wird dann das Ablenksystem ausgerichtet, so können sich die durch Magnetisieren erzielten Einstellwerte wieder verändern. Beim bisherigen Verfahren ist ein solcher Mangel kaum behebbar, da ja zum Magnetisieren des Magnetrings zunächst das Ablenksystem wieder vom Trichterteil abgezogen werden musste, womit auch der durch das Ablenksystem verursachte Fehler in den durch Magnetisieren erzielten Einstellwerten verschwand. Bei einer erfindungsgemässen Farbbildröhre kann dagegen eine einmal eingestellte Magnetisierung auch bei angebrachtem Ablenksystem beliebig korrigiert werden.This makes it possible to use an adjusting device in which the magnetizing device connects directly behind the deflection system aligning device at such a distance that the magnetizing process and the deflecting system aligning process can be carried out with the tube in the same position in the adjusting device. Only the tube without a deflection system, which is held by the deflection system alignment device before being attached to the funnel part, has to be inserted into the adjustment device, whereupon the magnetization and alignment of the deflection system can be carried out in one operation. This is of particular advantage because there may be interactions between the position of the deflection system and the values of color purity, grid and convergence once set by magnetizing the magnetic ring. If the magnetic ring was first magnetized to achieve the desired setting values and then the deflection system is aligned, the setting values achieved by magnetizing can change again. In the previous method, such a defect can hardly be remedied, since the deflection system first had to be pulled off the funnel part again in order to magnetize the magnetic ring, so that the error caused by the deflection system also disappeared in the setting values achieved by magnetization. In the case of a color picture tube according to the invention, on the other hand, a magnetization which has been set once can be corrected as desired even when the deflection system is attached.

Eine besonders günstige Lage des Magnetrings stellt, in Strahlrichtung gesehen, etwa die Mitte der Fokussierelektrode dar. In dieser Lage ist der Magnetring ausreichend weit von den elektronenstrahlerzeugenden Elektroden entfernt, die während des Herstellprozesses der Röhre ausgeglüht werden. Würde der Magnetring zu nahe bei diesen Elektroden liegen, so bestünde die Gefahr, dass er ebenfalls hoch erhitzt werden könnte und damit seine Magneteigenschaften erheblich ändern würde. Andererseits wäre es von Nachteil, wenn der Magnetring sehr nahe an der Anode, an der eine Spannung von 25 kV anliegt, liegen würde. Der Magnetring ist nämlich auf irgendeine Art und Weise zu befestigen, was eine Verformung der entsprechenden Elektrode an der Befestigungsstelle bedingt. Eine solche Verformung, z.B. eine Einkerbung in direkter Näher der Anode, kann zu Hochspannungsüberschlägen führen.A particularly favorable position of the magnetic ring, as seen in the beam direction, is approximately the center of the focusing electrode. In this position, the magnetic ring is sufficiently far away from the electrodes that generate electron beams, which are annealed during the production process of the tube. If the magnetic ring were too close to these electrodes, there would be a risk that it could also be heated to a high temperature and thus change its magnetic properties considerably. On the other hand, it would be a disadvantage if the magnetic ring were very close to the anode, which has a voltage of 25 kV. The magnetic ring is in fact to be fastened in some way, which causes a deformation of the corresponding electrode at the fastening point. Such deformation, for example a notch in the direct vicinity of the anode, can lead to high voltage flashovers.

Vorteile der Erfindung werden in der Figurenbeschreibung beschrieben und anhand von Figuren näher erläutert. Es zeigen:

  • Fig. 1 eine Seitenansicht einer Farbbildröhre mit einem Ablenksystem und einer Elektronenkanone, in deren Fokussiergitter ein Magnetring befestigt ist,
  • Fig. 2 eine Seitenansicht einer Elektronenkanone in Originalgrösse, in deren Fokussiergitter ein Magnetring befestigt ist; mit eingezeichnetem Massstab,
  • Fig. 3 einen Längsschnitt in Explosionsdarstellung durch das Fokussiergitter der Elektronenkanone gemäss Fig. 2,
  • Fig. 4 eine Draufsicht auf das Mittelteil der Fokussierelektrode gemäss Fig. 2 mit eingelegtem Magnetring,
  • Fig. 5 eine teilgeschnittene, teilschematische Seitenansicht einer Einstellvorrichtung mit eingesetzter Bildröhre, mit Magnetisiervorrichtung und Ablenksystemausrichtvorrichtung.
Advantages of the invention are described in the description of the figures and explained in more detail with reference to figures. Show it:
  • 1 is a side view of a color picture tube with a deflection system and an electron gun, in the focusing grid of which a magnetic ring is attached,
  • 2 shows a side view of an electron gun in its original size, in the focusing grid of which a magnetic ring is fastened; with drawn scale,
  • 3 shows a longitudinal section in an exploded view through the focusing grid of the electron gun according to FIG. 2,
  • 4 shows a plan view of the middle part of the focusing electrode according to FIG. 2 with an inserted magnetic ring,
  • Fig. 5 is a partially sectioned, partially schematic side view of an adjusting device with inserted picture tube, with magnetizing device and deflection system alignment device.

In Fig. 1 ist eine Farbbildröhre 10 dargestellt mit einem vorderen Bildschirm 11, einem konusförmigen Trichterteil 12 und einem hinteren Röhrenhals 13. Im Röhrenhals 13 ist eine Elektronenkanone 14 angebracht, die in der Seitenansicht gemäss Fig. 2 massstabsgetreu dargestellt ist. Am Übergang zwischen dem Röhrenhals 13 und dem Trichterteil 12 ist ein magnetisches Ablenksystem 15 angebracht. Es ist am Hals 13 durch eine Muffe 16 mit Schelle 17 befestigt. Das Ablenksystem 15 wird beim Fertigungsprozess der Farbbildröhre 10 zum Erzielen von Farbreinheit und dynamischer Konvergenz ausgerichtet und in der ausgerichteten Lage durch Befestigungskeile 66 aus Gummi gehalten, die zwischen das vordere Ende des Ablenksystems 15 und das Trichterteil 12 geschoben sind. Unter vorderem Ende des Ablenksystems 15 ist dabei das dem Bildschirm 11 zugewandte Ende zu verstehen. In entsprechendem Sinn werden in der ganzen Beschreibung die Bezeichnungen vorne und hinten verwendet werden. Es ist jedoch zu beachten, dass beim Aufbau der Elektronenkanone 14 in der Fachsprache statt hinten und vorne die Ausdrücke unten und oben verwendet werden, dies daher, da die Elektronenkanone 14 als Einzelteil in dieser Lage zusammengebaut und transportiert wird. Bei ihr wird also das dem Bildschirm 11 zugewandte Ende als oberes Ende bezeichnet.FIG. 1 shows a color picture tube 10 with a front screen 11, a conical funnel part 12 and a rear tube neck 13. In the tube neck 13 there is an electron gun 14 which is shown to scale in the side view according to FIG. 2. A magnetic deflection system 15 is attached to the transition between the tube neck 13 and the funnel part 12. It is attached to the neck 13 by a sleeve 16 with a clamp 17. The deflection system 15 is aligned during the manufacturing process of the color picture tube 10 to achieve color purity and dynamic convergence and is held in the aligned position by fastening wedges 66 made of rubber, which are pushed between the front end of the deflection system 15 and the funnel part 12. The front end of the deflection system 15 is to be understood as the end facing the screen 11. In a corresponding sense, the terms front and back will be used throughout the description. It should be noted, however, that when the electron gun 14 is used in technical terms, the terms below and above are used instead of back and front, because the electron gun 14 is assembled and transported as an individual part in this position. In this case, the end facing the screen 11 is referred to as the upper end.

Die Elektronenkanone 14 ist in Fig. 1 gestrichelt eingezeichnet und mit ihr in stark gestrichelter Linie ein Magnetring 19, der an ihr befestigt ist. Das neue an der dargestellten Farbbildröhre 10 gemäss Fig. 1 besteht darin, dass der Magnetring 19 an einer Stelle der Elektronenkanone 14 angebracht ist, an der er nicht mehr vom Ablenksystem 15 nach aussen hin abgedeckt ist. Gegenüber bisher bekannten Farbbildröhren 10 ist dies dadurch erfolgt, dass der Magnetring 19 in der Elektronenkanone 14 weiter nach unten verlegt worden ist, als dies bisher üblich war. Statt dessen kann aber auch ein Ablenksystem 15 verwendet werden, bei dem die Muffe 16 mit Schelle 17 gegenüber bisher bekannten Ablenksystemen 15 verkürzt ist. Auch ist es möglich, ein Ablenksystem zu verwenden, das vorne am Trichterteil 12 befestigbar ist und nicht hinten am Röhrenhals 13. Dadurch können die Muffe 16 mit Schelle 17 ganz wegfallen.The electron gun 14 is shown in dashed lines in FIG. 1 and with it in a strongly dashed line a magnetic ring 19 which is attached to it. The new feature of the color picture tube 10 shown in FIG. 1 is that the magnetic ring 19 is attached at a point on the electron gun 14 at which it is no longer covered by the deflection system 15 to the outside. Compared to previously known color picture tubes 10, this has been done by moving the magnetic ring 19 in the electron gun 14 further down than was previously the case. Instead, however, a deflection system 15 can also be used, in which the sleeve 16 with the clamp 17 is shortened compared to previously known deflection systems 15. It is also possible to use a deflection system which can be attached to the front of the funnel part 12 and not to the tube neck 13 at the rear. As a result, the sleeve 16 with the clamp 17 can be omitted entirely.

Der Magnetring 19 dient zum Einstellen von Farbreinheit, Konvergenz und Raster bei der Farbbildröhre 10. Er besteht aus einer Eisen-Kobalt-Vanadium- Legierung und wird von aussen, durch den Röhrenhals hindurch, so aufmagnetisiert, dass Farbreinheit, Raster und Konvergenz vorgegebene Einstellwerte einnehmen. Eine solche Einstellung ist bei der überwiegenden Anzahl von Farbbildröhren erforderlich, da nur äusserst wenige Farbbildröhren den Fertigungsprozess durchlaufen, ohne irgendwelche Abweichungen in Konvergenz, Farbreinheit und Raster aufzuweisen, bevor eine Korrektur durch ein Magnetfeld erfolgt ist. Das erzeugte Magnetfeld hat jedoch auch Einfluss auf die Schärfe der Elektronenstrahlen, die in ihrer Lage beeinflusst werden. Wird daher die Lage des Magnetrings 19 an der Elektronenkanone 14 verändert, müssen in der Regel auch Änderungen in der Geometrie der Elektronenkanone 14 und/oder der an ihr angelegten Spannungen vorgenommen werden. Abhängig von den verschiedenen Röhrentypen wird es daher bei manchen Typen technisch einfacher sein, das Ablenksystem so abzuändern, dass es nicht mehr den Magnetring überdeckt, da dieser in seiner Lage zum Beispiel wegen Schärfebedingungen nicht verlegt werden kann, oder bei anderen Röhren, bei denen ein solches Verlegen ohne Schwierigkeiten möglich ist, ist es vorteilhafter, das Ablenksystem in unveränderter Konstruktion zu belassen und statt dessen den Magnetring an eine Stelle der Elektronenkanone zu legen, an der er nicht mehr vom Ablenksystem überdeckt wird.The magnetic ring 19 is used to adjust the color purity, convergence and grid in the color picture tube 10. It consists of an iron-cobalt-vanadium alloy and is magnetized from the outside through the tube neck in such a way that the color purity, grid and convergence assume predetermined setting values . Such a setting is necessary for the majority of color picture tubes, since only very few color picture tubes go through the manufacturing process without showing any deviations in convergence, color purity and raster before a correction by a magnetic field has been carried out. However, the magnetic field generated also influences the sharpness of the electron beams, which are affected in their position. Therefore, if the position of the magnetic ring 19 on the electron gun 14 is changed, changes in the geometry of the electron gun 14 and / or the voltages applied to it must also be made. Depending on the different tube types, it will therefore be technically simpler for some types to modify the deflection system so that it no longer covers the magnetic ring, as this cannot be installed in its position, for example due to sharpening conditions, or for other tubes in which a such laying is possible without difficulty, it is more advantageous to leave the deflection system unchanged in construction and instead to place the magnetic ring at a point on the electron gun where it is no longer covered by the deflection system.

In den Figuren 2 bis 4 ist eine Elektronenkanone 14 dargestellt, an der ein Magnetring 19 an unterschiedlichen Stellen gut befestigbar ist.An electron gun 14 is shown in FIGS. 2 to 4, to which a magnetic ring 19 can be easily attached at different points.

Die Elektronenkanone 14 in Fig. 2 weist einen Pressglasteller 20 auf, in dem Kontaktierstifte 21 eingeschmolzen sind. Die Kontaktierstifte 21 sind mit Kontaktfahnen 22 leitend verbunden. Darüber schliessen sich eine Wehneltelektrode 23, eine Steuerelektrode 24, eine Fokussierelektrode 25, eine Anode 26 und ein Konvergenztopf 27 mit Kontaktfedern 28 an. Die Einzelteile der Elektronenkanone 14, also die Kontaktfahne 22 und die Elektroden 23 bis 26 werden durch zwei Glasstäbe 29 zusammengehalten, die im Fertigungsvorgang bis zur Erweichung erwärmt werden und in die dann die Öffnungsränder 30 der Elektroden eingedrückt werden. Von den beiden Glasstäben 29 ist in der Seitenansicht nur einer erkennbar. Der Konvergenztopf 27 ist durch Punktschweissung mit der Anode 26 verbunden. Der Übersichtlichkeit halber sind nicht sämtliche Verbindungen zwischen Kontaktstiften 21 und Kontaktfahnen 22 eingezeichnet und auch Kathoden und Heizer sind nicht dargestellt.The electron gun 14 in FIG. 2 has a pressed glass plate 20 in which contact pins 21 are melted. The contact pins 21 are conductively connected to contact tabs 22. This is followed by a Wehnelt electrode 23, a control electrode 24, a focusing electrode 25, an anode 26 and a convergence pot 27 with contact springs 28. The individual parts of the electron gun 14, that is to say the contact lug 22 and the electrodes 23 to 26, are held together by two glass rods 29 which are heated to softening in the manufacturing process and into which the opening edges 30 of the electrodes are then pressed. Only one of the two glass rods 29 can be seen in the side view. The convergence pot 27 is by spot welding solution connected to the anode 26. For the sake of clarity, not all connections between contact pins 21 and contact tabs 22 are shown, and cathodes and heaters are also not shown.

In die Fokussierelektrode 25 ist ein Magnetring 19 eingelegt, der in den Figuren 1 und 2 gestrichelt dargestellt ist, da er in der Seitenansicht von aussen nicht erkennbar ist. In den Figuren 3 und 4 ist der Magnetring 19 jedoch näher dargestellt. In der Explosionsdarstellung gemäss Fig. 3 ist der Aufbau der Fokussierelektrode 25 deutlicher dargestellt. Die Fokussierelektrode 25 besteht aus vier Elektrodenteilen 32 und einer Zwischenplatte 33.A magnetic ring 19 is inserted into the focusing electrode 25, which is shown in dashed lines in FIGS. 1 and 2, since it cannot be seen from the outside in the side view. However, the magnetic ring 19 is shown in more detail in FIGS. 3 and 4. The structure of the focusing electrode 25 is shown more clearly in the exploded view according to FIG. 3. The focusing electrode 25 consists of four electrode parts 32 and an intermediate plate 33.

Jedes Elektrodenteil 32 besteht aus einem Metalltopf mit Boden 35, Topfwand 36 und Öffnungsrand 30. In jedem Elektrodenteil 32 sind drei Strahldurchtrittsöffnungen 37 ausgespart, die kreisrunde Form besitzen, wie es in der Draufsicht gemäss Fig. 4 erkennbar ist. Durch die mittleren Strahldurchtrittsöffnungen 37.1 tritt ein mittlerer Elektronenstrahl 38.1, und durch die äusseren Strahldurchtrittsöffnungen 37.2 tritt jeweils ein äusserer Elektronenstrahl 38.2 durch. Entsprechend der Lage der drei Elektronenstrahlen 38 in einer Ebene liegen die Strahldurchtrittsöffnungen 37 in einem Elektrodenteil 32 jeweils nebeneinander, was zu einer ovalen Ausbildung des Elektrodenteils 32 führt. In der Seitenansicht gemäss Fig. 2, in der auf die Ebene, in der die Elektronenstrahlen 38 liegen, geblickt wird, sind die Elektroden 23 bis 26 nur geringfügig schmäler als der Konvergenztopf 27. In der Seitenansicht gemäss Fig. 1, in der die Ebene der Elektronenstrahlen 38 senkrecht zur Papierebene steht, erscheinen die Elektroden wegen der in Fig. 4 erkennbaren ovalen Ausführungsform gegenüber der kreisrunden Form des Konvergenztopfs 27 schmäler als der Konvergenztopf.Each electrode part 32 consists of a metal pot with bottom 35, pot wall 36 and opening edge 30. In each electrode part 32, three beam passage openings 37 are recessed, which have a circular shape, as can be seen in the top view according to FIG. 4. A central electron beam 38.1 passes through the central beam passage openings 37.1, and an outer electron beam 38.2 passes through the outer beam passage openings 37.2. Corresponding to the position of the three electron beams 38 in one plane, the beam passage openings 37 lie next to one another in an electrode part 32, which leads to an oval configuration of the electrode part 32. In the side view according to FIG. 2, in which the plane in which the electron beams 38 lie is looked at, the electrodes 23 to 26 are only slightly narrower than the convergence pot 27. In the side view according to FIG. 1, in the plane 4 is perpendicular to the plane of the paper, the electrodes appear narrower than the convergence pot compared to the circular shape of the convergence pot 27 because of the oval embodiment shown in FIG. 4.

Beim Zusammenbauen einer Fokussierelektrode 25 werden zunächst zwei Elektrodenteile 32 mit ihren Böden 35 aneinandergesetzt und zur Bildung eines Mittelteils 39 durch Punktschweissen miteinander verbunden. In das obere Elektrodenteil 32 dieses Mittelteils 39 wird dann der Magnetring 19 eingelegt und durch Einkerbungen 40 befestigt. Die Einkerbungen 40 sind in der Topfwand 36 so angebracht, dass sie direkt oberhalb des Magnetrings 19 ins Innere des Elektrodenteils 32 weisen. Auf den oberen Öffnungsrand 30 des Mittelteils 39 wird dann die Zwischenplatte 33 und ein als Oberteil 41 bezeichnetes Elektrodenteil 32 mit seinem Öffnungsrand 30 aufgesetzt. Entsprechend wird das vierte, als Unterteil 42 bezeichnete Elektrodenteil 32 mit seinem Öffnungsrand 30 auf den unteren Öffnungsrand des Mittelteils 39 aufgesetzt. Alle Teile werden dann durch die in die Offnungsränder 30 eingedrückten Glasstäbe 29 gehalten.When assembling a focusing electrode 25, two electrode parts 32 are first put together with their bottoms 35 and connected to one another by spot welding to form a central part 39. The magnetic ring 19 is then inserted into the upper electrode part 32 of this middle part 39 and fastened by means of notches 40. The notches 40 are made in the pot wall 36 in such a way that they point directly above the magnetic ring 19 into the interior of the electrode part 32. The intermediate plate 33 and an electrode part 32, referred to as the upper part 41, with its opening edge 30 are then placed on the upper opening edge 30 of the middle part 39. Correspondingly, the fourth electrode part 32, referred to as the lower part 42, is placed with its opening edge 30 on the lower opening edge of the central part 39. All parts are then held by the glass rods 29 pressed into the opening edges 30.

Die Form des Magnetrings 19 und seine Befestigung durch Einkerbungen 40 sind in den Figuren 3 und 4 erkennbar. Der Magnetring 19 besteht aus zwei gleichen Magnetringteilen 19.1, die zusammen einen ovalen Ring bilden. Die Magnetringteile 19.1 stossen mit ihren Enden unter Einhaltung jeweils eines Luftspalts 43 aneinander. Der Übersichtlichkeit halber sind die Luftspalte 43 sehr gross eingezeichnet, so dass es erscheinen mag, als würden die Enden der Magnetringteile 19.1 nicht direkt aneinander liegen.The shape of the magnetic ring 19 and its attachment by notches 40 can be seen in FIGS. 3 and 4. The magnetic ring 19 consists of two identical magnetic ring parts 19.1, which together form an oval ring. The ends of the magnet ring parts 19.1 abut one another with an air gap 43. For the sake of clarity, the air gaps 43 are drawn very large, so that it may appear that the ends of the magnet ring parts 19.1 are not directly adjacent to one another.

Eine Elektronenkanone 14 mit dem beschriebenen Aufbau hat den Vorteil, dass der Magnetring 19 an beliebiger Stelle der Fokussierelektrode 25 untergebracht werden kann, ohne dass wesentliche Einflüsse auf die Schärfe der Elektronenstrahlen 38 zu verzeichnen sind. Besonders vorteilhaft ist die dargestellte und bisher beschriebene Lage des Magnetrings 19 etwa in der Mitte der Fokussierelektrode 25. Weniger vorteilhaft sind Lagen am Boden des Unterteils 42 oder des Oberteils 41. Wird der Magnetring 19 nämlich in das Oberteil 41 eingelegt und mit Einkerbungen 40 befestigt, so besteht die Gefahr von Hochspannungsüberschlägen zwischen den Einkerbungen 40 und der auf 25 kV liegenden Anode 26. Bei einer Elektronenkanone 14 gemäss dem Ausführungsbeispiel liegt an der Fokussierelektrode 25 eine Spannung von etwa 7 kV an. Es finden jedoch auch Elektronenkanonen 14 in grossem Umfang Verwendung, bei denen die Fokussierelektrode 25 kürzer ausgebildet ist und bei denen an ihr nur etwa 4,5 kV anliegen. Dies ist jedoch unerheblich für die neue Farbbildröhre, da es bei ihr allein darauf ankommt, dass der Magnetring nicht nach aussen hin durch das Ablenksystem 15 verdeckt wird.An electron gun 14 with the structure described has the advantage that the magnetic ring 19 can be accommodated at any point on the focusing electrode 25 without having any significant effects on the sharpness of the electron beams 38. The illustrated and previously described position of the magnetic ring 19 approximately in the middle of the focusing electrode 25 is particularly advantageous. Layers on the bottom of the lower part 42 or the upper part 41 are less advantageous. If the magnetic ring 19 is inserted into the upper part 41 and fastened with notches 40, there is a risk of high-voltage flashovers between the notches 40 and the anode 26, which is at 25 kV. In the case of an electron gun 14 according to the exemplary embodiment, a voltage of approximately 7 kV is present at the focusing electrode 25. However, electron guns 14 are also used to a large extent, in which the focusing electrode 25 is shorter and in which only about 4.5 kV are applied to it. However, this is irrelevant for the new color picture tube, since all that is important is that the magnetic ring is not covered from the outside by the deflection system 15.

Die Lage des Magnetrings 19 am Boden 35 des Unterteils 42 ist daher in der Regel von weniger Vorteil, da beim Fertigungsgang üblicher Röhren 10 die, nicht eingezeichneten, Kathoden und damit die Wehneltelektrode 23 und die Steuerelektrode 24 stark erhitzt werden. Dabei besteht die Gefahr, dass auch das Unterteil 42 und mit ihm ein eingelegter Magnetring 19 erhitzt wird, wodurch dieser seine magnetischen Eigenschaften erheblich ändern würde. Bei Röhren, bei denen kein Ausheizen stattfindet, besteht diese Gefahr allerdings nicht.The position of the magnet ring 19 on the bottom 35 of the lower part 42 is therefore generally of less advantage, since in the course of the production of conventional tubes 10 the cathodes (not shown) and thus the Wehnelt electrode 23 and the control electrode 24 are heated to a great extent. There is a risk that the lower part 42 and with it an inserted magnetic ring 19 will also be heated, as a result of which this would change its magnetic properties considerably. However, this danger does not exist with tubes where there is no baking out.

Aus den vorgenannten Gründen ist also die Befestigung des Magnetrings 29 im mittleren Bereich der Fokussierelektrode 25 von besonderem Vorteil. Dazu kann der Magnetring 19 entweder, wie dargestellt, am Boden 35 des oberen Elektrodenteils 32 des Mittelteils 39 oder am Boden des unteren Elektrodenteils 32 des Mittelteils 39 befestigt sein. Auch eine Befestigung oben oder unten an der Zwischenplatte 33 kann vorgenommen sein, wozu zweckmässigerweise Laschen aus dem Rand der Zwischenplatte 33 umgebogen sind, die den Magnetring 19 festhalten. Derartige Lagen und Befestigungsmöglichkeiten sind in den Figuren jedoch nicht näher dargestellt. Sie sind für die neue Röhre auch unerheblich, da es ja nur auf die Lage des Magnetrings 19 in bezug auf das Ablenksystem 15 ankommt.For the aforementioned reasons, the attachment of the magnetic ring 29 in the central region of the focusing electrode 25 is of particular advantage. For this purpose, the magnetic ring 19 can either be fastened, as shown, to the bottom 35 of the upper electrode part 32 of the middle part 39 or to the bottom of the lower electrode part 32 of the middle part 39. Fastening at the top or bottom of the intermediate plate 33 can also be carried out, for which purpose tabs are expediently bent out of the edge of the intermediate plate 33 and hold the magnetic ring 19 in place. Such positions and attachment options are not shown in the figures. They are also irrelevant for the new tube, since it is only a matter of the position of the magnet ring 19 in relation to the deflection system 15.

Für die neue Röhre, bei der der Magnetring 19 nicht vom Ablenksystem 15 abgedeckt ist, ist es auch nicht erheblich, ob es sich um eine Dünnhalsfarbbildröhre mit etwa 29 mm Halsaussendurchmesser oder um eine Dickhalsröhre mit etwa 36 mm Halsaussendurchmesser oder z.B. eine Trinitronröhre oder eine Mehrstrahl-Oszillographenröhre handelt. Im Ausführungsbeispiel gemäss den Figuren 2 bis 4 isteine Elektronenkanone 14 für eine Dünnhalsröhre dargestellt. In diesem Fall weist der Magnetring 19 einen langen Innendurchmesser von 20,45 mm und einen kurzen Innendurchmesser von 9,4 mm auf. Der kreisrunde Konvergenztopf hat 27 mm Durchmesser. Der Magnetring 19 kann innen oder aussen an der Elektronenkanone befestigt sein und er kann aus einem oder mehreren Magnetringteilen bestehen. Seine Befestigung ist an die Art der Elektrode anzupassen, an der er angebracht wird. Dabei ist zu beachten, dass bei Elektronenkanonen häufig auch plattenförmige Elektroden statt den topfförmigen Elektroden gemäss der dargestellten Ausführungsform Verwendung finden.For the new tube, in which the magnetic ring 19 is not covered by the deflection system 15, it is also irrelevant whether it is a thin-necked color picture tube with about 29 mm outside of the neck diameter or a thick-necked tube with an outside diameter of about 36 mm or, for example, a Trinitron tube or a multi-beam oscillograph tube. In the exemplary embodiment according to FIGS. 2 to 4, an electron gun 14 for a thin-necked tube is shown. In this case, the magnetic ring 19 has a long inner diameter of 20.45 mm and a short inner diameter of 9.4 mm. The circular convergence pot has a diameter of 27 mm. The magnetic ring 19 can be attached to the inside or outside of the electron gun and it can consist of one or more magnetic ring parts. Its attachment must be adapted to the type of electrode to which it is attached. It should be noted that plate-shaped electrodes are often used instead of the cup-shaped electrodes according to the illustrated embodiment in electron guns.

Entsprechend wie die genaue Ausführungsform einer Elektronenkanone und des an ihr befestigten Magnetrings 19 nicht erheblich ist, genauso kommt es auch auf die genaue Ausführungsform des Ablenksystems nicht an, solange nur der Magnetring nicht vom Ablenksystem abgedeckt wird. So können Ablenksysteme verwendet werden, bei denen sowohl die Spulenpaare für die Horizontal- wie auch die für die Vertikalablenkung durch Sattelspulen gebildet sind, wie auch Ablenksysteme verwendet werden können, die Toroid- und Sattelspulen aufweisen. Letztere werden jedoch im Regelfall günstiger sein, da diese kombinierten Spulen häufig kürzer gebaut werden können als Ablenksysteme, die nur Sattelspulen aufweisen. Bei Verwendung der kürzeren Ablenksysteme ist aber auch die Bedingung leichter einzuhalten, dass der Magnetring nicht vom Ablenksystem überdeckt wird. Auch auf die Befestigungsart des Ablenksystems kommt es nicht hauptsächlich an. Es ist jedoch besonders vorteilhaft, ein Ablenksystem zu verwenden, das mit seinem vorderen Teil am Trichterteil 12 einer Farbbildröhre 10 befestigt wird. Damit fallen nämlich Befestigungsmittel am hinteren Ende weg, wodurch die Bedingung leichter einzuhalten ist, dass der Magnetring nicht vom Ablenksystem überdeckt sein soll.Just as the exact embodiment of an electron gun and the magnetic ring 19 attached to it is not significant, the exact embodiment of the deflection system is also irrelevant as long as the magnetic ring is not covered by the deflection system. Deflection systems can thus be used in which both the coil pairs for the horizontal and for the vertical deflection are formed by saddle coils, and also deflection systems can be used which have toroidal and saddle coils. However, the latter will generally be cheaper, since these combined coils can often be made shorter than deflection systems that only have saddle coils. When using the shorter deflection systems, however, the condition that the magnetic ring is not covered by the deflection system is easier to meet. The type of attachment of the deflection system is also not the main issue. However, it is particularly advantageous to use a deflection system which is attached with its front part to the funnel part 12 of a color picture tube 10. This eliminates the need for fasteners at the rear end, which makes it easier to meet the condition that the magnetic ring should not be covered by the deflection system.

Der besondere Vorteil einer neuen Kathodenstrahlröhre 10 besteht darin, dass bei ihr sämtliche Einstellvorgänge für den Magnetring 19 und das Ablenksystem 15 auf einfachste Art und Weise auf einer gemeinsamen Einstellvorrichtung 44 vorgenommen werden können. Eine Einstellvorrichtung 44 ist teilschematisch in Fig. 5 dargestellt. Auf einem Vorrichtungstisch 45 ist eine Schlittenführung 46 für einen Röhrenaufnahmeschlitten 47 und eine Führungsstange 48 zum Führen einer Ablenksystemausrichtvorrichtung 49 montiert. Die Schlittenführung 46 und die Führungsstange 48 lassen Verschiebungen des Röhrenaufnahmeschlittens 47 und der Ablenksystemausrichtvorrichtung 49 in Richtung der Röhrenlängsachse 18 zu.The particular advantage of a new cathode ray tube 10 is that all of the setting operations for the magnetic ring 19 and the deflection system 15 can be carried out in the simplest manner on a common setting device 44. An adjusting device 44 is shown partially schematically in FIG. 5. A carriage guide 46 for a tube receiving carriage 47 and a guide rod 48 for guiding a deflection system alignment device 49 are mounted on a device table 45. The slide guide 46 and the guide rod 48 allow displacements of the tube receiving slide 47 and the deflection system alignment device 49 in the direction of the longitudinal axis 18 of the tube.

Ablenksystemausrichtvorrichtungen sind z.B. aus der US-A-3 992 578 oder der EP-A-0 021 275 bekannt. Eine der letzteren Vorrichtung ähnliche Ablenksystemausrichtvorrichtung 49 ist in Fig. 5 teilschematisch dargestellt. Auf der Führungsstange 48 ist ein Führungsschlitten verschiebbar, an dem eine rechtwinklig zur Röhrenlängsachse 18 stehende Lagerplatte 50 befestigt ist. Die Lagerplatte 50 weist eine kugelkalottenförmige Lagerfläche 51 auf, in der ein Aufnahmering 52 kardanisch gelagert ist. Am Aufnahmering 52 greifen über einen Zapfen 53 durch einen Pfeil 54 dargestellte Verstellkräfte an, durch die die kardanische Bewegung des Aufnahmerings 52 durchgeführt wird. Der Verstellmechanismus ist der Übersichtlichkeit halber nicht näher dargestellt. In der Regel sind Mechanismen vorhanden, durch die es möglich ist, die Verstellung des Aufnahmerings 52 von der Bildschirmseite der Einstellvorrichtung 44 herzu bedienen.Deflection system alignment devices are e.g. known from US-A-3 992 578 or EP-A-0 021 275. A deflection system alignment device 49 similar to the latter device is shown in partial schematic form in FIG. 5. A guide slide can be displaced on the guide rod 48, to which a bearing plate 50 which is perpendicular to the longitudinal axis 18 of the tube is fastened. The bearing plate 50 has a spherical cap-shaped bearing surface 51, in which a receiving ring 52 is gimbal-mounted. Adjusting forces, represented by an arrow 54, act on the receiving ring 52 via a pin 53, by means of which the cardanic movement of the receiving ring 52 is carried out. The adjustment mechanism is not shown for the sake of clarity. As a rule, mechanisms are available by which it is possible to operate the adjustment of the receiving ring 52 from the screen side of the setting device 44.

Am Aufnahmering 53 sind Spannbacken 55 verstellbar befestigt. Diese Spannbacken 55 dienen zum Befestigen eines Ablenksystems 15 im Aufnahmering. Ein ebenfalls dargestelltes Ablenksystem 15 weist zu diesem Zweck an seinem hinteren Ende einen Spannring 56 auf, der in eine Ausnehmung in der Aufnahmeplatte eingesetzt ist und durch die verstellten Spannbacken 55 gehalten ist. Der Verstellmechanismus der Spannbacken 55 ist ebenfalls der Übersichtlichkeit halber nicht dargestellt.Clamping jaws 55 are adjustably attached to the receiving ring 53. These clamping jaws 55 are used to fasten a deflection system 15 in the receiving ring. For this purpose, a deflection system 15, also shown, has a clamping ring 56 at its rear end, which is inserted into a recess in the receiving plate and is held by the adjusted clamping jaws 55. The adjustment mechanism of the jaws 55 is also not shown for the sake of clarity.

Die Einstellvorrichtung 44 weist weiterhin Kontaktiervorrichtungen 57 auf, und zwar eine Anodenkontaktiervorrichtung 57.1 und eine Halskontaktiervorrichtung 57.2. Die Anodenkontaktiervorrichtung 57.1 ist vorrichtungsfest isoliert gelagert, was jedoch ebenfalls nicht näher dargestellt ist. Die Halskontaktiervorrichtung 57.2 ist über eine Kontaktiervorrichtungshalterung 58 mit der Führungsstange 48 verschiebefest verbunden. Am oberen Ende der Kontaktiervorrichtungshalterung 58 sitzt ein Bolzenführungskopf 59, in den eine an der Halskontaktiervorrichtung befestigte Pinole 60 eingreift. Die Pinole 60 ist verschiebbar in dem Bolzenführungskopf 59 gelagert und wird durch die Kraft einer nicht dargestellten Feder zur Bildschirmseite der Einstellvorrichtung 44 bis zu einem Anlagepunkt vorgedrückt.The adjusting device 44 also has contacting devices 57, specifically an anode contacting device 57.1 and a neck contacting device 57.2. The anode contact device 57.1 is mounted insulated in a device-fixed manner, but this is also not shown in detail. The neck contacting device 57.2 is connected to the guide rod 48 in a non-displaceable manner via a contacting device holder 58. At the upper end of the contact device holder 58 there is a bolt guide head 59, into which a sleeve 60 attached to the neck contact device engages. The sleeve 60 is displaceably mounted in the bolt guide head 59 and is pressed forward by the force of a spring, not shown, to the screen side of the adjusting device 44 up to a contact point.

Vor der Halskontaktiervorrichtung 57.2 sitzt in einem durch Abstandsstifte 61 vorgegebenen Abstand eine Magnetisiervorrichtung 62. Derartige Vorrichtungen sind z.B. in der DE-A-26 12 607 oder der DE-A-28 32 667 beschrieben. Eine solche Magnetisiervorrichtung 62 weist Magnetisierspulen 63 auf, die gestrichelt im Inneren der Magnetisierspule schematisch dargestellt sind. Die Magnetisierspulen 63 weisen in der Regel eine grössere Anzahl elektrischer Anschlüsse 64 auf, von denen jedoch nur zwei eingezeichnet sind.A magnetizing device 62 sits in front of the neck contacting device 57.2 at a distance predetermined by spacing pins 61. Such devices are e.g. described in DE-A-26 12 607 or DE-A-28 32 667. Such a magnetizing device 62 has magnetizing coils 63, which are shown schematically in dashed lines inside the magnetizing coil. The magnetizing coils 63 generally have a large number of electrical connections 64, of which only two are shown.

Die Halskontaktiervorrichtung 57.2 ist in ihrer Lage so angebracht, dass eine auf den Röhrenaufnahmeschlitten 47 gesetzte Farbbildröhre beim Einschieben in die Einstellvorrichtung mit ihren Kontaktierstiften 21 gerade in die Halskontaktiervorrichtung 57.2 eingreift und diese dabei gegen den Druck der Feder im Bolzenführungskopf 59 etwas nach hinten drückt. Durch diese Gegenkraft ist ein sicheres Kontaktieren und ein sicherer Sitz der Farbbildröhre 10 in der Einstellvorrichtung 44 gewährleistet. Auch die Anodenkontaktvorrichtung 57.1 ist so angebracht, dass sie beim Einschieben der Röhre 10 gerade den am Trichterteil 12 angebrachten Anodenkontakt 65 kontaktiert. Die Magnetisiervorrichtung 62 ist so an der Halskontaktiervorrichtung 57.2 befestigt, dass der Röhrenhals 13 zentrisch durch eine Aussparung der Magnetisiervorrichtung 62 dringt, wenn die Röhre 10 mit ihren Kontaktierstiften 21 in die Halskontaktiervorrichtung 57.2 greift.The neck contacting device 57.2 is mounted in its position in such a way that a color picture tube placed on the tube receiving carriage 47 engages with the contacting pins 21 in the adjusting device 47.2 when it is inserted into the adjusting device, thereby engaging the neck contacting device 57.2 presses slightly against the pressure of the spring in the bolt guide head 59. This counterforce ensures reliable contact and a secure fit of the color picture tube 10 in the adjusting device 44. The anode contact device 57.1 is also mounted such that it just contacts the anode contact 65 attached to the funnel part 12 when the tube 10 is inserted. The magnetizing device 62 is fastened to the neck contacting device 57.2 such that the tube neck 13 penetrates centrally through a recess in the magnetizing device 62 when the tube 10 engages with the contacting pins 21 in the neck contacting device 57.2.

Die Ablenksystemausrichtvorrichtung 49 hält ein Ablenksystem 15 so, dass eine Farbbildröhre 10 bei ihrem Einsetzen in die Einstellvorrichtung 44 mit ihrem Hals 13 ungehindert durch das Ablenksystem 15 hindurchgreifen kann. Der Abstand 67 zwischen Ablenksystemausrichtvorrichtung 49 und Magnetisiervorrichtung 62 ist so gewählt, dass die Magnetisiervorrichtung 62 gerade über dem Magnetring 19 steht, wenn sich das Ablenksystem 15 in der richtigen Lage über dem Trichterteil 12 befindet. Damit der konstruktiv erforderliche Abstand eingehalten werden kann, ist es von Vorteil, wenn der Magnetring mindestens 5 mm hinter dem hinteren Ablenksystemende liegt.The deflection system alignment device 49 holds a deflection system 15 such that a color picture tube 10 can reach with its neck 13 through the deflection system 15 unimpeded when it is inserted into the adjustment device 44. The distance 67 between the deflection system alignment device 49 and the magnetization device 62 is selected such that the magnetization device 62 is just above the magnetic ring 19 when the deflection system 15 is in the correct position above the funnel part 12. In order to be able to maintain the required distance, it is advantageous if the magnetic ring is at least 5 mm behind the rear end of the deflection system.

Ein Einstellvorgang auf der beschriebenen Einstellvorrichtung 44 wird nun beschrieben. Unter Bildschirmseite der Einstellvorrichtung wird dabei im folgenden die Seite verstanden, auf der sich der Bildschirm 11 einer eingesetzten Farbbildröhre 10 befindet. Zunächst ist der Röhrenaufnahmeschlitten 47 mit der Schlittenführung 46 ganz zur Bildschirmseite her aus der Einstellvorrichtung 44 herausgezogen. Die Spannbacken 55 sind so verstellt, dass ein Ablenksystem 15 mit seinem Spannring 56 in den Aufnahmering 52 eingesetzt werden kann. Daraufhin wird zunächst ein Ablenksystem 15 in den Aufnahmering 52 eingesetzt und durch Verstellen der Spannbacken 55 festgehalten. Anschliessend wird eine Röhre 10 auf den Röhrenaufnahmeschlitten 47 aufgesetzt und in die Einstellvorrichtung 44 so weit eingeschoben, bis die Kontaktierstifte 21 in die Halskontaktiervorrichtung 57.2 eingreifen und schliesslich die Röhre 10, durch Eingreifen einer nicht dargestellten Raste in den Aufnahmeschlitten 47, festgehalten wird. Gleichzeitig legt sich die Anodenkontaktiervorrichtung 57.2 an den Anodenkontakt 65 an. Mit dem Einschnappen der Raste werden automatisch die Betriebsspannungen an die Röhre 10 angelegt.A setting operation on the setting device 44 described will now be described. The screen side of the setting device is understood below to mean the side on which the screen 11 of an inserted color picture tube 10 is located. First of all, the tube receiving slide 47 with the slide guide 46 is pulled out of the adjusting device 44 all the way to the screen side. The clamping jaws 55 are adjusted so that a deflection system 15 with its clamping ring 56 can be inserted into the receiving ring 52. Then a deflection system 15 is first inserted into the receiving ring 52 and held in place by adjusting the clamping jaws 55. A tube 10 is then placed on the tube receiving carriage 47 and pushed into the adjusting device 44 until the contact pins 21 engage the neck contacting device 57.2 and finally the tube 10 is held in place by engaging a not-shown notch in the receiving carriage 47. At the same time, the anode contact device 57.2 contacts the anode contact 65. When the catch snaps into place, the operating voltages are automatically applied to tube 10.

In einem ersten Arbeitsgang wird der Magnetring 19 mit Hilfe der Magnetisiervorrichtung 62 so aufmagnetisiert, dass Farbreinheit, Raster und Konvergenz auf vorgegebene Werte eingestellt sind. Danach wird das Ablenksystem 15 nach vorgegebenen Einstellkriterien ausgerichtet. Bei der dargestellten Ablenksystemausrichtvorrichtung 49 ist dabei eine Bewegung des Ablenksystems 15 in Richtung der Röhrenlängsachse 18 und eine Kippbewegung in bezug auf die Röhrenlängsachse möglich. Bei anderen Arten von Ablenksystemen müssen dagegen zum Ausrichten Bewegungen in Richtung der Röhrenlängsachse 18 und zwei dazu senkrechten Richtungen erfolgen. Nach dem Ausrichten des Ablenksystems 15 wird dieses mit dem Röhrenhals 13 über die Muffe 16 mit Schelle 17 und mit dem Trichterteil 12 durch untergelegte Befestigungskeile 66 verbunden.In a first operation, the magnet ring 19 is magnetized with the aid of the magnetizing device 62 in such a way that color purity, screen and convergence are set to predetermined values. The deflection system 15 is then aligned according to predetermined setting criteria. In the illustrated deflection system alignment device 49, a movement of the deflection system 15 in the direction of the longitudinal axis 18 of the tube and a tilting movement with respect to the longitudinal axis of the tube is possible. In other types of deflection systems, on the other hand, movements in the direction of the longitudinal axis 18 of the tube and two directions perpendicular thereto must take place for alignment. After the deflection system 15 has been aligned, it is connected to the tube neck 13 via the sleeve 16 with a clamp 17 and to the funnel part 12 by means of fastening wedges 66 placed underneath.

Das Einstellen einer Farbbildröhre 10, bei der das Magnetisieren und das Ausrichten des Ablenksystems gleichzeitig, aber unabhängig voneinander auf einer einzigen Einstellvorrichtung 44 ausgeführt werden können, bringt besondere Vorteile mit sich. Es tritt nämlich verschiedentlich der Fall auf, dass durch das nach dem Magnetisieren des Magnetrings 19 ausgerichtete Ablenksystem 15 die Elektronenstrahlen in der durch die Magnetisierung erzielten Lage von Raster, Farbreinheit oder statischer Konvergenz verstellt werden. Diesen Fehler können bei bisher bekannten Röhren nicht durch Nachmagnetisieren behoben werden, da ja der Magnetring durch das Ablenksystem abgedeckt ist. Bei Verwendung einer hier beschriebenen Röhre können jedoch der Magnetisiervorgang des Magnetrings 19 und der Ausrichtvorgang des Ablenksystems 15 unabhängig voneinander und gleichzeitig ohne Probleme ausgeführt werden. Es kann auch der Fall auftreten, dass beim Einstellen der dynamischen Konvergenz durch Ausrichten des Ablenksystems 15 Fehler auftreten, die nur durch Ausrichten des Ablenksystems nicht in den Toleranzbereich zurückgeführt werden können, was jedoch möglich ist, wenn die durch das Magnetisieren des Magnetrings 19 eingestellte statische Konvergenz durch Ummagnetisieren etwas verändert wird. Dadurch wird dann zwar die statische Konvergenz etwas verschlechtert, allerdings noch innerhalb der Toleranzgrenze, aber auch die dynamische Konvergenz kann innerhalb ihre Toleranzgrenze gebracht werden. Ein solcher Ausgleich von Fehlern, die sowohl durch den Magnetring 19 wie auch durch das Ablenksystem 15 beeinflussbar sind, lassen sich nur bei Verwendung einer Röhre der hier beschriebenen Art, bei der also der Magnetring 19 nicht vom Ablenksystem 15 überdeckt ist, beheben, bei der das Magnetisieren und das Ausrichten des Ablenksystems auf einer Einstellvorrichtung der angegebenen Art gleichzeitig und unabhängig voneinander vorgenommen werden können.Setting a color picture tube 10, in which the magnetization and the alignment of the deflection system can be carried out simultaneously but independently of one another on a single setting device 44, has particular advantages. This is because the deflection system 15 aligned after the magnetization of the magnetic ring 19 magnetically adjusts the electron beams in the position of the grid, color purity or static convergence achieved by the magnetization. In the case of previously known tubes, this error cannot be remedied by post-magnetization, since the magnetic ring is covered by the deflection system. When using a tube described here, however, the magnetization process of the magnet ring 19 and the alignment process of the deflection system 15 can be carried out independently of one another and simultaneously without problems. It can also happen that when adjusting the dynamic convergence by aligning the deflection system 15 errors occur which cannot be returned to the tolerance range only by aligning the deflection system, but this is possible if the static one set by magnetizing the magnetic ring 19 Convergence is changed by remagnetizing something. As a result, the static convergence is then somewhat deteriorated, but still within the tolerance limit, but the dynamic convergence can also be brought within its tolerance limit. Such compensation of errors that can be influenced both by the magnetic ring 19 and by the deflection system 15 can only be remedied when using a tube of the type described here, in which case the magnetic ring 19 is not covered by the deflection system 15, in which the magnetization and the alignment of the deflection system can be carried out simultaneously and independently of one another on an adjusting device of the specified type.

Claims (2)

1. Cathode-ray tube, particularly colour-picture tube (10), comprising a screen panel (11), a cone-shaped funnel section (12) and a rear neck section (13) housing an electron gun (14) with a focusing electrode (25) and other electrodes for producing at least two electron beams (38), a magnetic deflection system (15) located at the junction region of the funnel section (12) with the neck section (13) and serving to deflect the electron beams (38) over the screen panel (11), and a magnetic ring (19) attached to the electron gun (14) outside the neck area covered by the deflection system (15), characterized in that the focusing electrode (25) comprises four cup-shaped electrode parts (32) each having a bottom (35), a wall (36) and a rim (30), that two of the electorde parts (32) are placed one on top of the other at their bottoms (35) and joined together to form a central part (39), that the rims (30) of the two other electrode parts (32), which form an upper part (41 ) facing the screen panel (11) and a lower part (42), respectively, are placed on and joined to the corresponding rims (30) of the central part (39), and that the magnetic ring (19) is secured to the inside of the bottom (35) of one of the two electrode parts (32) forming the central part (39).
2. A Cathode-ray tube, particularly a colour-picture tube (10), comprising a screen panel (11), a cone-shaped funnel section (12) and a rear neck section (13) housing an electron gun (14) with a focusing electrode (25) and other electrodes for producing at least two electron beams (38), a magnetic deflection system (15) located at the junction region of the funnel section (12) with the neck section (13) and serving to deflect the electron beams (38) over the screen panel (11), and a magnetic ring (19) attached to the electron gun (14) outside the neck area covered by the deflection system (15), characterized in that the focusing electrode (25) comprises four cup-shaped electrode parts (32) each having a bottom (35), a wall (36) and a rim (30), that two of the electrode parts (32) are placed one on top of the other at their bottoms (35) and joined together to form a central part (39), that the rim (30) of an additional electrode part (32), forming an upper part (41) facing the screen panel (11), is placed on and joined to the corresponding rim (30) of the central part (39) with an intermediate plate (33) being placed therebetween, that the rim (30) of the last electrode part (32), which forms a lower part (42), is placed on and joined to the corresponding rim (30) of the central part (39) and that the magnetic ring (19) is attached to the intermediate plate (33).
EP82104948A 1981-06-12 1982-06-05 Cathode ray tube with magnetic ring Expired EP0068182B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3123298 1981-06-12
DE19813123298 DE3123298A1 (en) 1981-06-12 1981-06-12 CATHODE RAY TUBES WITH MAGNETIC RING

Publications (2)

Publication Number Publication Date
EP0068182A1 EP0068182A1 (en) 1983-01-05
EP0068182B1 true EP0068182B1 (en) 1985-11-27

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EP82104948A Expired EP0068182B1 (en) 1981-06-12 1982-06-05 Cathode ray tube with magnetic ring

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US (1) US4591755A (en)
EP (1) EP0068182B1 (en)
JP (1) JPS5814450A (en)
CA (1) CA1194076A (en)
DE (2) DE3123298A1 (en)

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Publication number Priority date Publication date Assignee Title
US4833364A (en) * 1984-04-04 1989-05-23 Hitachi, Ltd. Electron gun for color picture tubes having uniquely formed lens apertures
NL8500807A (en) * 1985-03-20 1986-10-16 Philips Nv PICTURE TUBE.

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US3992578A (en) * 1976-01-08 1976-11-16 General Instrument Of Canada Ltd. Yoke mounting apparatus
DE2612607C3 (en) * 1976-03-25 1984-01-12 Philips Patentverwaltung Gmbh, 2000 Hamburg Static convergence correction device in color television picture display tubes
US4396862A (en) * 1978-05-01 1983-08-02 Rca Corporation Color picture tube with means for affecting magnetic deflection fields in electron gun area
DE2924949A1 (en) * 1979-06-21 1981-01-15 Standard Elektrik Lorenz Ag DEVICE FOR ADJUSTING THE DIFFERENTIAL SYSTEM OF A COLOR IMAGE TUBE
DE3003197A1 (en) * 1980-01-30 1981-08-06 Standard Elektrik Lorenz Ag, 7000 Stuttgart DEVICE FOR ADJUSTING THE ELECTRON BEAMS OF A COLOR IMAGE TUBE
US4370593A (en) * 1980-12-30 1983-01-25 Rca Corporation In-line electron gun and method for modifying the same

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CA1194076A (en) 1985-09-24
EP0068182A1 (en) 1983-01-05
DE3267668D1 (en) 1986-01-09
US4591755A (en) 1986-05-27
JPS5814450A (en) 1983-01-27
DE3123298A1 (en) 1983-01-05

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