EP0403010A1 - Verfahren zur Herstellung einer Bildröhre sowie Bildröhre - Google Patents

Verfahren zur Herstellung einer Bildröhre sowie Bildröhre Download PDF

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Publication number
EP0403010A1
EP0403010A1 EP90201495A EP90201495A EP0403010A1 EP 0403010 A1 EP0403010 A1 EP 0403010A1 EP 90201495 A EP90201495 A EP 90201495A EP 90201495 A EP90201495 A EP 90201495A EP 0403010 A1 EP0403010 A1 EP 0403010A1
Authority
EP
European Patent Office
Prior art keywords
parts
display tube
shield
magnetic
shadow mask
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP90201495A
Other languages
English (en)
French (fr)
Inventor
Theodoor Christiaan Anna Hens
Martinus Cornelis Maria Verhoeven
Paulus Hendricus Maria Verheggen
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.)
Koninklijke Philips NV
Original Assignee
Philips Gloeilampenfabrieken NV
Koninklijke Philips Electronics NV
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 Philips Gloeilampenfabrieken NV, Koninklijke Philips Electronics NV filed Critical Philips Gloeilampenfabrieken NV
Publication of EP0403010A1 publication Critical patent/EP0403010A1/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/06—Screens for shielding; Masks interposed in the electron stream

Definitions

  • the invention relates to a method of producing a display tube having an inner magnetic shield comprising two complementary parts.
  • the invention also relates to a display tube and more specifically to a display tube produced in accordance with such a method.
  • An inner magnetic shield comprising two complementary parts placed at a short distance opposite each other serves to screen an electron beam generated in a display tube from exterior magnetic fields, such as for example the magnetic field of the earth.
  • the magnetic screening depends on the value of the distance between the two parts. To avoid unwanted influences of magnetic fields on the path of the electron beam, it is important for this distance to be substantially not subjected to changes during operation and throughout the operating life of the display tube.
  • a method of the type defined in the opening paragraph is characterized, in that the two parts are placed facing one another while forming a non-magnetic gap therebetween, and that the two parts are interconnected by elements of a non-magnetic material which bridge the gap whereafter the magnetic shield is secured in the display tube.
  • this ensures that the distance between the parts remains sufficiently constant throughout the operating life of the display tube.
  • the two parts of the magnetic shield form one integral whole before they are suspended, whilst maintaining the magnetic screening function, and are therefore easy to handle, which simplifies fitting of the shield in the display tube. Also an accurate and firm connection the two parts with the desired mutual spacing is provided between in a simple manner.
  • a preferred embodiment of a method according to the invention, whereby the two parts are interconnected firmly in a simple and fast manner, is characterized in that interconnection of the parts is effected by attaching a non-magnetic metal or metal alloy to the parts.
  • a further preferred embodiment of a method according to the invention in which a shadow mask provided with a large plurality of apertures is fitted in the display tube during one manufacturing step, is characterized in that the shield is fitted in the display tube whilst mechanically being uncoupled from the shadow mask. This prevents vibrations in the shadow mask being passed on to the dual shield. These vibrations might cause an unwanted change in the interspacing of the shield parts.
  • the invention provides a display tube having an envelope with a display window, an electrode system generating at least one electron beam and an inner magnetic shield located between the electrode system and the display window, which shield includes two complementary parts which are placed spaced apart facing each other, the display tube providing an adequately constant magnetic screening throughout its operating life when it is characterized in that the two parts are interconnected by elements of a non-magnetic metal or metal alloy.
  • a display tube having an envelope with a display window, a shadow mask provided with a large plurality of apertures fitted in the envelope, an electrode system for generating at least one electron beam and an inner magnetic shield fitted in the envelope and being located between the electrode system and the shadow mask, the shield comprising two interspaced opposing complementary parts, which according to the invention is preferably characterized in that the shield is fitted in the envelope without being mechanically coupled to the shadow mask and in that the two parts are interconnected by elements of a non-magnetic material, evidences an accurate colour purity of a picture to be displayed and has a magnetic shielding which is not susceptible to vibrations in the shadow mask.
  • a simple, mechanically uncoupled connection of the shadow mask and the magnetic shield in the display tube is obtained in a preferred embodiment of a display tube according to the invention, in that the shadow mask is provided with flexible elements which are connected to supporting means provided in the display window, and in that the parts of the shield are each provided with suspension means each connected to a relevant supporting element.
  • the mechanical stability of the two parts of the magnetic shield is sufficiently high in a display tube according to the invention when it is characterized in that the two parts of the magnetic shield are interconnected at least their free ends.
  • the two parts of the magnetic shield are interconnected along substantially the overall length of their facing sides. This improves the mechanical stability of the connection between the two parts of the magnetic shield to a still further extent.
  • the colour picture tube shown in a cross-sectional view in Fig. 1 has an envelope with a substantially rectangular display window 1, a cone 2, and a neck 3.
  • the neck 3 contains an electrode system 4 having three electron guns for generating three electron beams 5, 6 and 7.
  • the electron beams are generated in one plane (in this case the plane of drawing), and are directed to an internal display screen 8 which is applied on the display window 1 and consists of a large number of phosphor elements which are coated with an aluminium layer 20 and luminesce in red, green and blue.
  • the phosphor elements are, for example, in the form of strips and the longitudinal direction of the strip-like elements is perpendicular to the plane through the electron gun (the plane of drawing here).
  • the electron beams 5, 6 and are deflected on to the picture screen 8 with the aid of a plurality of deflection coils 9 arranged coaxially around the tube axis, and pass through a shadow mask 10 constituted by a thin metal plate 11, whose longitudinal direction extends parallel to the phosphor elements of the display screen 8.
  • the three electron beams 5, 6 and 7 pass through the apertures 11 at a slight angle to each other and consequently each impinge on only phosphor elements of one colour.
  • a dual internal magnetic shield 19 which in this embodiment is in the form of a truncated cone and has a substantially rectangular end is provided with a flange 21.
  • the dual internal shield 19 reduces the detrimental effects of external magnetic fields, such as, for example, the magnetic field of the earth, on the electron beam path.
  • the internal shield 19 is fastened by means of its flange 21 in each of its corners to a supporting strip 12 of the shadow mask supporting arrangement.
  • the inner shield 19 comprises two complementary parts 15, 16 which are placed facing each other spaced apart by a distance d.
  • the magnetic shielding depends on the value of this distance d. In practice it was found that it is possible to ensure in a simple manner that this distance d remains constant during the operating life of the display tube, when during manufacture of the display tube the parts 15 and 16 are first interconnected by means of elements 17 of a non-magnetic material so that the magnetic shield 19 is formed (as is shown schematically in Fig.
  • a curable synthetic resin material can, for example, be used as the material of which the elements 17 are produced.
  • elements of a non-magnetic metal or metal alloy are used which are secured to the two parts of the shield, for example by welding, which in a simple way provides an adequate mechanical stability of the dual shield.
  • An alloy of Cr, Ni and Fe is particularly suitable because of its non-magnetic properties and the fact that it can be worked in a simple manner.
  • non-magnetic materials to be used and the compositions of the metal alloys can be of many different types and that consequently the invention is not limited to the examples given.
  • the elements 17 can, for example, be plates in the form of strips or small circles which can be connected to both the interior side and the exterior side of the parts 15 and 16.
  • connection between the two parts 15 and 16 is preferably obtained by using four elements 35 which interconnect the free ends of the parts 15 and 16, as shown schematically in Fig. 3.
  • the mechanical stability of the connection is still further improved when the two parts of the magnetic shield are interconnected substantially along the overall length of their facing sides.
  • This connection can be realised by one adequately large or several smaller elements of a non-magnetic material.
  • the shadow mask 10 and also the shield 19 are generally made of thin metal sheets, they are both very susceptible to vibrations and shocks.
  • the shadow mask 10 is preferably, in accordance with the invention, fitted in the display tube without being mechanically coupled to the shield 19, which is shown schematically in Fig. 4.
  • the shadow mask 10 is fitted in the display tube by means of flexible elements 22 applied in the corners of the shadow mask 10.
  • Each flexible element 22 is connected to a supporting element 23 applied in the corresponding corner of the display window 1.
  • the dual shield 19 is connected in the display tube by means of the flange 21 and supporting elements 24 which are applied in, for example, the corners of the display window 1.
  • the flange 21 may directly be connected to the supporting elements 24 or, in a different embodiment, with the aid of a suspension means, for example a flat resilient element.
  • the mechanical stability of the dual shield 19 is indeed ensured, in accordance with the invention, by connecting the two parts and 16 of the shield 19 to elements 17 made of a non-magnetic material.
  • the supporting elements 23 and 24 may be different supporting elements, but preferably the shield 19 and the shadow mask are fitted in the display tube with the aid of the same supporting elements 25 as is shown schematically in Fig. 5.
  • Each supporting element 25 is, for example, provided with a cone-shaped free end 26 to which the flexible elements 22 are connected.
  • the shadow mask 10 is connected to a carrier frame 29, which carrier frame 29 is provided in its corners with the flexible elements 22.
  • the shield 19 is provided with a flange 28 to which suspension means 27 (for example flexible elements) are connected, the supporting means themselves being connected to the free end 26 of the relevant supporting element 25.
  • suspension means 27 for example flexible elements
  • the invention is described with reference to a colour picture tube having a shadow mask.
  • the invention however also relates to a display tube without shadow mask for the display of monochrome images.

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  • Electrodes For Cathode-Ray Tubes (AREA)
EP90201495A 1989-06-16 1990-06-11 Verfahren zur Herstellung einer Bildröhre sowie Bildröhre Withdrawn EP0403010A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL8901524 1989-06-16
NL8901524A NL8901524A (nl) 1989-06-16 1989-06-16 Werkwijze voor het vervaardigen van een beeldbuis, en beeldbuis.

Publications (1)

Publication Number Publication Date
EP0403010A1 true EP0403010A1 (de) 1990-12-19

Family

ID=19854845

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90201495A Withdrawn EP0403010A1 (de) 1989-06-16 1990-06-11 Verfahren zur Herstellung einer Bildröhre sowie Bildröhre

Country Status (3)

Country Link
EP (1) EP0403010A1 (de)
JP (1) JPH0330244A (de)
NL (1) NL8901524A (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0518431A1 (de) * 1991-06-14 1992-12-16 Koninklijke Philips Electronics N.V. Verfahren zum Herstellen einer magnetisch gespalteten innenmagnetischen Abschirmkappe für Bildwiedergaberöhre
DE4219337A1 (de) * 1991-06-11 1992-12-17 Mitsubishi Electric Corp Farbkathodenstrahlroehre
EP0570065A1 (de) * 1992-05-15 1993-11-18 Koninklijke Philips Electronics N.V. Farbbildröhre mit innerer magnetischer Abschirmung
WO2003100809A1 (en) * 2002-05-24 2003-12-04 Koninklijke Philips Electronics N.V. Internal magnetic shield for crt
CN101540255B (zh) * 2009-04-21 2012-03-28 彩虹显示器件股份有限公司 一种用于彩色显像管内屏蔽的省料设计方法
US10044147B2 (en) 2013-01-31 2018-08-07 Te Connectivity Corporation Slotted shield

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2000902A (en) * 1977-07-01 1979-01-17 Hitachi Ltd Colour picture tube

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2000902A (en) * 1977-07-01 1979-01-17 Hitachi Ltd Colour picture tube

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 12, no. 217 (E-624)(3064) 21 June 1988, & JP-A-63 013238 (HITACHI SEISAKUSHO K.K.) 20 January 1988, *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4219337A1 (de) * 1991-06-11 1992-12-17 Mitsubishi Electric Corp Farbkathodenstrahlroehre
US5336963A (en) * 1991-06-11 1994-08-09 Mitsubishi Denki Kabushiki Kaisha Color cathode-ray tube
DE4219337C2 (de) * 1991-06-11 1998-02-26 Mitsubishi Electric Corp Farbkathodenstrahlröhre
EP0518431A1 (de) * 1991-06-14 1992-12-16 Koninklijke Philips Electronics N.V. Verfahren zum Herstellen einer magnetisch gespalteten innenmagnetischen Abschirmkappe für Bildwiedergaberöhre
US5389025A (en) * 1991-06-14 1995-02-14 U.S. Philips Corporation Method of manufacturing a magnetically split internal magnetic shield for a display tube
EP0570065A1 (de) * 1992-05-15 1993-11-18 Koninklijke Philips Electronics N.V. Farbbildröhre mit innerer magnetischer Abschirmung
WO2003100809A1 (en) * 2002-05-24 2003-12-04 Koninklijke Philips Electronics N.V. Internal magnetic shield for crt
CN101540255B (zh) * 2009-04-21 2012-03-28 彩虹显示器件股份有限公司 一种用于彩色显像管内屏蔽的省料设计方法
US10044147B2 (en) 2013-01-31 2018-08-07 Te Connectivity Corporation Slotted shield

Also Published As

Publication number Publication date
JPH0330244A (ja) 1991-02-08
NL8901524A (nl) 1991-01-16

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