EP0570065B1 - Tube image en couleur muni d'un blindage magnétique interne - Google Patents

Tube image en couleur muni d'un blindage magnétique interne Download PDF

Info

Publication number
EP0570065B1
EP0570065B1 EP93201325A EP93201325A EP0570065B1 EP 0570065 B1 EP0570065 B1 EP 0570065B1 EP 93201325 A EP93201325 A EP 93201325A EP 93201325 A EP93201325 A EP 93201325A EP 0570065 B1 EP0570065 B1 EP 0570065B1
Authority
EP
European Patent Office
Prior art keywords
display screen
aperture
wall
display tube
colour
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 - Lifetime
Application number
EP93201325A
Other languages
German (de)
English (en)
Other versions
EP0570065A1 (fr
Inventor
Adrianus Johannes c/o Int. Van Mensvoort
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
Koninklijke Philips Electronics NV
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 Koninklijke Philips Electronics NV, Philips Electronics NV filed Critical Koninklijke Philips Electronics NV
Priority to EP93201325A priority Critical patent/EP0570065B1/fr
Publication of EP0570065A1 publication Critical patent/EP0570065A1/fr
Application granted granted Critical
Publication of EP0570065B1 publication Critical patent/EP0570065B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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 colour display tube comprising:
  • a colour selection means is herein understood to mean, for example, an apertured shadow mask sheet or a wire mask.
  • the ratio between the dimension of the long central axis and the dimension of the short central axis of the display screen characterizes the picture format.
  • Modern display tubes are provided with an internal magnetic shielding structure (shield) to limit the deviation of the electron path due to the earth's magnetic field.
  • a complete shielding is not possible due to an aperture which is required for passing the electron beam.
  • a horizontally directed spot displacement caused by the lateral earth's magnetic produces a risk of discolouration (N effect) in the corners only.
  • the internal residual field can be influenced by means of an additional measure in such a way that the electron beam still passes the mask at the desired angle. This measure involves, for example the use of a shield with "vertically" directed slits (situated in a plane parallel to the short axis of the display screen) such as in document EP-A-0 217 473.
  • the internal residual field is then influenced in such a way that there is less spot displacement in the horizontal direction.
  • the slits enhance the magnetic resistance in the shield material in the horizontal direction so that there is more spot displacement in the vertical direction.
  • the shield is split fully magnetically ("split shield"). Overcompensation of the N effect may then even occur.
  • a problem of "vertically" directed slits is that the slit length is to be limited to ensure the mechanical stability of the shield so that an unacceptable spot displacement remains in the corners, particularly in large tubes.
  • large tubes having a picture diagonal of 41 cm or mor such as 80 FS ("Flat Square") and 36 inch WS ("Wide Screen") it has been attempted to lengthen the slits to a maximum extent and to restore the resultant loss of mechanical strength by welding on supporting strips of non-ferromagnetic material such as in document EP-A-0 403 010.
  • the following problems then occur.
  • a display tube of the type described in the opening paragraph is therefore characterized in that the magnetic resistance of the wall being locally higher than at both sides of the elongate aperture between at least one end of the elongate aperture and the adjacent edge of the wall.
  • the magnetic resistance of the wall for the lateral field can be increased in different ways, for example, by
  • a very effective measure appears to be the provision of a transverse slit between at least one end of the elongate aperture and the adjacent edge of the wall.
  • a transverse slit may be provided at the gun side, at the display screen side or at both sides of the slit-shaped aperture. The effect is greatest at the display screen side because this is closest to the location where influence should be exerted on the electron beam.
  • the effect of the measures according to the invention is enhanced if the shield is made of a sheet material.
  • Fig. 1 shows a colour display tube 1 having a glass envelope which comprises a neck portion 2 accommodating an electron gun system 3, a funnel-shaped portion 4 within which a magnetic shield 5 is arranged, and a window portion 6 whose inner surface is provided with a display screen 7 having a pattern of phosphors arranged along parallel lines.
  • a shadow mask 8 is arranged opposite the display screen 7.
  • the shape of the magnetic shield 5 in display tube 1 roughly follows the contours of the funnel-shaped portion.
  • Modern display tubes are provided with an internal magnetic shield to reduce the deviation of the electron path due to the earth's magnetic field. A complete shielding is not possible due to the apertures required for the electron beams. In a lateral field only the horizontally directed spot displacement in the corners causes a risk of discolouration (N effect).
  • the internal residual field is influenced via an additional measure in such a way that the electron beam still passes the mask at the desired angle.
  • Fig. 2A shows an example of a shield 9 in a rear view, in which no residual field correction is realised.
  • Fig. 2B shows the associated spot displacement in the corners, similarly as in a lateral earth's magnetic field.
  • Fig. 2C shows a shield 5 with vertically directed slits 10a, 10b.
  • the internal residual field is influenced thereby in such a way that there is less spot displacement in the horizontal direction.
  • the slits increase the magnetic resistance in the shield material in the horizontal direction so that there is more spot displacement in the vertical direction (Fig. 2D).
  • this is not important for line tubes because it does not cause discolouration.
  • Fig. 2E shows the shield 25 split completely magnetically. Overcompensation of the N effect may even occur in this case (see Fig. 2F).
  • a problem of the vertically directed slits is that the slit length is to be limited to ensure the mechanical stability of the shield so that an unacceptable spot displacement remains in the corners, particularly in large tubes.
  • the mechanical stability can be restored by welding on supporting strips of a non-ferromagnetic material.
  • the slits are not extended any more than is justified in connection with the mechanical stability of the shield and the magnetic resistance for the lateral field in alignment with the afore-mentioned vertically directed slits is enhanced by
  • Figs. 3A to 3B show some embodiments. Their use is attractive in all "line” tubes with a screen diagonal from 41 cm onwards, particularly in tubes having an aspect ratio of more than 4:3, such as 14:9 and 16:9.
  • Fig. 3A is an elevational view of a corner portion of a shield 30 having a long side wall 31 provided with an elongate transversal aperture, or slit 32.
  • This treatment may be a mechanical deformation (for example, by means of a centre punch) or a deformation by means of a laser beam, or diffusion of a non-magnetic material (for example, Al).
  • a shield with two (or more) - particularly shorter - slits 62, 62' can be used in this embodiment (Fig. 3D).
  • Fig. 3B is an elevational view of a corner portion of a shield 40 having a long side wall 41 in which a "vertical" slit 42 is provided.
  • slit 42 is provided with a T-shaped end 44 in which the cross-piece of the T has a length l2 of several tens of millimetres (for example, 40).
  • Fig. 3C is an elevational view of a corner portion of a shield 50 having a long side wall 51 in which a "vertical" slit 52 is provided.
  • an auxiliary slit 54 having a length l3 of several tens of millimetres (for example, 40 to 80) and a width of several millimetres (for example, 3) is arranged transversely to the slit 52 between one end of the slit 52 and the opposite edge 53.
  • the length ( i.e . the dimension transverse to the axis of the vertical "major” slits) of the transverse slits is smaller than the length of the "vertical" slits in all these cases. This is favourable for the mechanical stability of the shield.
  • the shield may be formed from one part or, for example, from two parts (cf. 2E). In the latter case the two shield parts (cf. 2E). In the latter case the two shield parts (which are U-shaped in that case) may be fixed to each other in such a way that the afore-mentioned elongate aperture, or apertures is, or are formed at the area of fixation.

Landscapes

  • Electrodes For Cathode-Ray Tubes (AREA)

Claims (6)

  1. Tube image couleur (1) comprenant :
    une enveloppe avec un axe longitudinal, ayant une partie de col (2), une partie conique (4) et une partie à fenêtre (6);
    un canon électronique (3) agencé dans la partie de col;
    un écran d'affichage (7) ayant un petit axe et un grand axe et un motif de lignes de luminophores parallèles à un axe de l'écran d'affichage sur la surface interne de la partie à fenêtre;
    un moyen de sélection de couleurs (8) agencé à proximité de l'écran d'affichage;
    une structure de blindage magnétique (5, 30, 40, 50) agencée à l'intérieur de la partie conique, ladite structure de blindage ayant deux parties de paroi longues parallèles au grand axe de l'écran d'affichage et deux parties de paroi courtes parallèles au petit axe de l'écran d'affichage, et une ouverture à son extrémité côté canon, ladite ouverture s'étendant transversalement à l'axe longitudinal et constituant une ouverture pour le passage des faisceaux d'électrons produits par le canon et le balayage de l'écran d'affichage, chacune desdites parties de paroi longues de la structure de blindage ayant au moins une ouverture oblongue (10A, 10B, 32, 42, 52, 62, 62') qui s'étend transversalement à la direction longitudinale de la paroi et est distante des bords de la paroi, caractérisé en ce que la résistance magnétique de la paroi est plus élevée localement qu'au niveau des deux côtés de l'ouverture oblongue entre au moins une extrémité de l'ouverture oblongue et le bord voisin (33, 53) de la paroi.
  2. Tube image couleur selon la revendication 1, caractérisé en ce que la résistance magnétique est augmentée localement en aménageant une fente transversale (54) entre au moins une extrémité d'au moins une ouverture oblongue et le bord voisin (53) de la paroi.
  3. Tube image couleur selon la revendication 2, caractérisé en ce qu'une fente transversale est agencée du côté de l'écran d'affichage de ladite au moins une ouverture oblongue.
  4. Tube image couleur selon la revendication 2, caractérisé en ce que la fente transversale a une longueur plus courte que l'ouverture oblongue.
  5. Tube image couleur selon la revendication 1, caractérisé en ce que la résistance magnétique est augmentée localement par déformation mécanique.
  6. Tube image couleur selon la revendication 1, caractérisé en ce que la résistance magnétique est augmentée localement par diffusion d'une matière non magnétique.
EP93201325A 1992-05-15 1993-05-07 Tube image en couleur muni d'un blindage magnétique interne Expired - Lifetime EP0570065B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP93201325A EP0570065B1 (fr) 1992-05-15 1993-05-07 Tube image en couleur muni d'un blindage magnétique interne

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EP92201386 1992-05-15
EP92201386 1992-05-15
EP93201325A EP0570065B1 (fr) 1992-05-15 1993-05-07 Tube image en couleur muni d'un blindage magnétique interne

Publications (2)

Publication Number Publication Date
EP0570065A1 EP0570065A1 (fr) 1993-11-18
EP0570065B1 true EP0570065B1 (fr) 1996-04-10

Family

ID=26131393

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93201325A Expired - Lifetime EP0570065B1 (fr) 1992-05-15 1993-05-07 Tube image en couleur muni d'un blindage magnétique interne

Country Status (1)

Country Link
EP (1) EP0570065B1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0650180B1 (fr) * 1993-10-22 1997-09-17 Koninklijke Philips Electronics N.V. Tube d'affichage en couleur muni d'un blindage magnétique
TW434631B (en) * 1996-11-30 2001-05-16 Lg Electronics Inc Flat cathode-ray tube
WO2007027184A1 (fr) * 2005-08-31 2007-03-08 Thomson Licensing Écran magnétique interne de dispositif d’affichage à balayage orthogonal

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4622490A (en) * 1985-02-28 1986-11-11 Rca Corporation Cathode-ray tube with an internal magnetic shield
DE3677310D1 (de) * 1985-10-03 1991-03-07 Philips Corp Farbbildroehre mit innerer magnetischer abschirmung.
NL8901524A (nl) * 1989-06-16 1991-01-16 Philips Nv Werkwijze voor het vervaardigen van een beeldbuis, en beeldbuis.

Also Published As

Publication number Publication date
EP0570065A1 (fr) 1993-11-18

Similar Documents

Publication Publication Date Title
US3005921A (en) Cathode-ray tubes of the focus-mask variety
US5363010A (en) Color display tube having an internal magnetic shield
EP0570065B1 (fr) Tube image en couleur muni d'un blindage magnétique interne
US5434470A (en) Colour display tube having an internal magnetic shield
US5412276A (en) Color display tube having an internal magnetic shield
CA1271512A (fr) Construction a ressort connectant a un cadre de soutien une electrode de selection de couleur de tube d'affichage en couleurs
EP0247793B1 (fr) Tube à rayons cathodiques muni d'un blindage magnétique interne
KR940000301B1 (ko) 샤도우 마스크의 프레임 어셈블리 지지부를 가진 칼라 화상 튜브
CA2044469C (fr) Methode de fabrication de masques perfores de tube image couleur a bords de perforations ameliorees
US4645968A (en) Vibration control of color picture tube shadow mask
EP0651422B1 (fr) Tube image en couleurs muni d'un blindage magnétique externe
JPH06103912A (ja) カラー陰極線管
US5557161A (en) Color display tube having a magnetic sheild with a reduced magnetic permeability area
US5910702A (en) Color cathode ray tube having an improved shadow mask and shadow mask connector
US6310433B1 (en) Inner shield for a cathode ray tube and method for manufacturing the same
US4491764A (en) Arc suppression structure for an electron gun
KR940010981B1 (ko) 칼라 음극선관
CA1125348A (fr) Table cathodique a masque strie a espacement masque-ecran accru
KR100731661B1 (ko) 프레임에 부착된 장력 마스크를 구비하는 컬러 수상관
EP0595405A1 (fr) Tube à rayons cathodiques couleurs
KR930011792B1 (ko) 칼라 음극선관
US5000711A (en) Method of making color picture tube shadow mask having improved tie bar locations
KR940008155Y1 (ko) 칼라 음극선관용 새도우마스크 프레임 조립체
EP0650180B1 (fr) Tube d'affichage en couleur muni d'un blindage magnétique
JPH10261369A (ja) 内部磁気シールド構体およびそれを備えた陰極線管

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB IT

17P Request for examination filed

Effective date: 19940509

17Q First examination report despatched

Effective date: 19950529

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB IT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRE;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.SCRIBED TIME-LIMIT

Effective date: 19960410

REF Corresponds to:

Ref document number: 69302128

Country of ref document: DE

Date of ref document: 19960515

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: FR

Ref legal event code: CD

REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

REG Reference to a national code

Ref country code: FR

Ref legal event code: D6

REG Reference to a national code

Ref country code: GB

Ref legal event code: 746

Effective date: 20021107

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20040527

Year of fee payment: 12

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20040528

Year of fee payment: 12

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20040714

Year of fee payment: 12

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050507

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20051201

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20050507

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20060131

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20060131