EP1138797A1 - Masking device for a colour flat screen cathode ray tube comprising a tension-type iron-nickel-alloy shadow mask - Google Patents

Masking device for a colour flat screen cathode ray tube comprising a tension-type iron-nickel-alloy shadow mask Download PDF

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Publication number
EP1138797A1
EP1138797A1 EP01400812A EP01400812A EP1138797A1 EP 1138797 A1 EP1138797 A1 EP 1138797A1 EP 01400812 A EP01400812 A EP 01400812A EP 01400812 A EP01400812 A EP 01400812A EP 1138797 A1 EP1138797 A1 EP 1138797A1
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EP
European Patent Office
Prior art keywords
alloy
shadow mask
hardened
support frame
temperature
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Application number
EP01400812A
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German (de)
French (fr)
Inventor
Ricardo Cozar
Pierre-Louis Reydet
Lucien Coutu
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Aperam Stainless Precision SAS
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Imphy Ugine Precision SA
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Publication of EP1138797A1 publication Critical patent/EP1138797A1/en
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/10—Ferrous alloys, e.g. steel alloys containing cobalt
    • C22C38/105—Ferrous alloys, e.g. steel alloys containing cobalt containing Co and Ni
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
    • 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
    • H01J29/07—Shadow masks for colour television tubes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/07—Shadow masks
    • H01J2229/0722—Frame
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/07—Shadow masks
    • H01J2229/0727—Aperture plate
    • H01J2229/0733—Aperture plate characterised by the material

Definitions

  • the present invention relates to a masking device for a tube cathode color display flat screen, of the type comprising a frame support for a stretched shadow mask and a stretched shadow mask mounted on the support frame.
  • Color display cathode ray tubes have, so known, a display screen provided with photophores, an electron gun producing 3 electron beams and a masking device, consisting of a shadow mask mounted on a support frame, placed opposite the screen of display and intended to ensure good quality of the image viewed.
  • the shadow mask consists of a metal sheet pierced with a plurality of holes or slits through which the 3 electron beams pass to excite the photophores arranged on the screen. The quality of the image obtained is all the more better than the alignment between the lanterns, the holes in the shadow mask and the electron beams are precise.
  • the shadow mask When the viewing tube is in functioning, a significant part of the electron beams is intercepted by the shadow mask, which generates local heating of it which can distort it and therefore deteriorate the quality of the displayed image.
  • the quality of the image may also be deteriorated by the vibrations of the shadow mask caused by various sources of vibration.
  • the shadow mask To obtain images of good quality, the shadow mask must on the one hand be not very sensitive to local heating, on the other hand, have a natural frequency of vibration high enough that the amplitude of these vibrations does not disturb the color of images by misalignment of electron beams, holes in the shadow mask and tealight holders.
  • the shadow mask When the viewing screen is curved, the shadow mask has a shape which matches that of the screen, and the problems of sensitivity to overheating and vibration are resolved by making the shadow mask by stamping a sheet of Fe-Ni alloy with a very low coefficient of expansion pierced with holes.
  • the shadow mask is simply welded to a support frame which exerts no effort on the shadow mask. The frame can therefore be light, which presents benefits.
  • the shadow mask can be a sheet not stamped fixed for example by welding on a support frame previously compressed which then exerts a tension on the shadow mask.
  • the shadow mask is then said to be "stretched".
  • the tension of the shadow mask is intended, on the one hand to solve the problem of sensitivity to local heating, and on the other hand to increase the natural frequency of vibration of the shadow mask for attenuate the amplitude of these vibrations.
  • This solution requires in particular the use of a material whose characteristics make it possible to maintain a tension sufficient in the operating temperature range of the cathode ray tube (approximately 100 ° C), and this after heating to approximately 600 ° C during of the cathode ray tube manufacturing process.
  • the mounted shadow mask stretched on its support frame is heated for the first time to around 600 ° C to cause an oxidation called "blackening", then a second time at around 450 ° C, after assembly of the assembly in the cathode ray tube, during sealing of the screen slab on the glass cone and finally a third time at around 380 ° C when vacuuming the cathode ray tube.
  • blackening an oxidation called "blackening”
  • the support frame of generally rectangular shape, comprises two end posts on which the shadow mask is fixed and two posts side which maintain the spacing of the end posts.
  • the shadow mask also generally rectangular in shape, is attached to the end posts, usually by welding, along two of its sides opposites. In any event, the tension exerted on the shadow mask in the longitudinal direction creates tension in the transverse direction.
  • the object of the present invention is to remedy these drawbacks by proposing a means for manufacturing a stretched shadow mask and its support frame not very sensitive to local heating, having a natural frequency of vibration suitable and having good flatness after high temperature heating resulting from manufacturing operations.
  • the subject of the invention is a masking device for a cathode ray tube for color display on a flat screen, of the type comprising a support frame for a stretched shadow mask and a stretched shadow mask mounted on the support frame. so as to be subjected to a voltage at room temperature.
  • the support frame is made of hardened Fe-Ni alloy having a coefficient of thermal expansion between 20 ° C and 150 ° C less than 5x10 -6 / K and an elastic limit Rp0.2 at 20 ° C greater than 700 MPa.
  • the stretched shadow mask is made of Fe-Ni alloy having a coefficient of thermal expansion between 20 ° C and 150 ° C less than 3x10 -6 / K.
  • the hardened Fe-Ni alloy of which the support frame is made and the Fe-Ni alloy of which the shadow mask is made are chosen so that, below a temperature T 1 , the mean coefficient of expansion ⁇ 20-T , between 20 ° C and temperature T, of the hardened Fe-Ni alloy of which the support frame is made is greater than the average coefficient of expansion ⁇ 20-T , between 20 ° C and temperature T, of l 'Fe-Ni alloy of which the shadow mask is made; above said temperature T 1 , the average coefficient of expansion ⁇ 20-T , between 20 ° C and the temperature T, of the hardened Fe-Ni alloy of which the support frame is made is lower than the average coefficient of expansion ⁇ 20 -T , between 20 ° C and temperature T, of the Fe-Ni alloy from which the shadow mask is made; said temperature T 1 is less than 350 ° C, and preferably less than 300 ° C.
  • the hardened Fe-Ni alloy of which the support frame is made up is an FeNi alloy of the "hardened ⁇ '" type, the chemical composition of which comprises, by weight: 40.5% ⁇ Ni + Co + Cu ⁇ 43.5% 0% ⁇ Co ⁇ 5% 0% ⁇ Cu ⁇ 3% 1.5% ⁇ Ti ⁇ 3.5% 0.05% ⁇ Al ⁇ 1% C ⁇ 0.05%
  • the Fe-Ni alloy of which the shadow mask is made is an Fe-Ni alloy, the composition of which comprises, by weight: 32% ⁇ Ni + Co + Cu ⁇ 37% 0% ⁇ Co ⁇ 5.5% 0% ⁇ Cu ⁇ 2% 0% ⁇ Nb + Ta + Mo + W + Zr ⁇ 2% 0 ⁇ Mn ⁇ 0.5% If ⁇ 0.2% C ⁇ 0.02% S ⁇ 0.01% P ⁇ 0.02%
  • the composition of which comprises, by weight: 40.5% ⁇ Ni + Co + Cu ⁇ 43.5% 0% ⁇ Co ⁇ 5% 0% ⁇ Cu
  • the chemical composition of the Fe-Ni alloy from which the shadow mask is made can, for example, be such that: 32% ⁇ Ni + Co + Cu ⁇ 35.5% 0% ⁇ Co ⁇ 4% 0% ⁇ Cu ⁇ 2% 0% ⁇ Nb + Ta + Mo + W + Zr ⁇ 0.2%
  • the chemical composition of the Fe-Ni alloy from which the shadow mask is made can also be such that: 33.5% ⁇ Ni + Co + Cu ⁇ 37% 0% ⁇ Co ⁇ 5.5% 0% ⁇ Cu ⁇ 2% 0.2% ⁇ Nb + Ta + Mo + W + Zr ⁇ 2%
  • the hardened Fe-Ni alloy of which the support frame is made up can be a FeNi alloy of the “hardened ⁇ '” type, the chemical composition of which comprises, by weight: 43.5% ⁇ Ni + Co + Cu ⁇ 45.5% 0% ⁇ Co ⁇ 5% 0% ⁇ Cu ⁇ 3% 1.5% ⁇ Ti ⁇ 3.5% 0.05% ⁇ Al ⁇ 1% C ⁇ 0.05%
  • the Fe-Ni alloy of which the shadow mask is made up can be an Fe-Ni alloy, the composition of which comprises, by weight: 35.5% ⁇ Ni + Co + Cu ⁇ 37% 0% ⁇ Co ⁇ 5.5% 0% ⁇ Cu ⁇ 2% 0 ⁇ Mn ⁇ 0.5%
  • ⁇ 0.2% C ⁇ 0.02% S ⁇ 0.01% P ⁇ 0.02% The rest being iron and impurities resulting from processing.
  • the invention also relates to a stretched shadow mask consisting of an Fe-Ni alloy, the chemical composition of which comprises, by weight: 32% ⁇ Ni + Co + Cu ⁇ 37% 0% ⁇ Co ⁇ 5.5% 0% ⁇ Cu ⁇ 2% 0% ⁇ Nb + Ta + Mo + W + Zr ⁇ 2% 0 ⁇ Mn ⁇ 0.5% If ⁇ 0.2% C ⁇ 0.02% S ⁇ 0.01% P ⁇ 0.02% The rest being iron and impurities resulting from processing.
  • the chemical composition of the Fe-Ni alloy from which the shadow mask is made may preferably be such that: 32% ⁇ Ni + Co + Cu ⁇ 35.5% 0% ⁇ Co ⁇ 4% 0% ⁇ Cu ⁇ 2% 0% ⁇ Nb + Ta + Mo + W + Zr ⁇ 0.2%
  • the chemical composition of the Fe-Ni alloy from which the shadow mask is made can also be such that: 33.5% ⁇ Ni + Co + Cu ⁇ 37% 0% ⁇ Co ⁇ 5.5% 0% ⁇ Cu ⁇ 2% 0.2% ⁇ Nb + Ta + Mo + W + Zr ⁇ 2%
  • the frame can also be made of a hardened Fe-Ni alloy of the type "Hardened beryllium”, “hardened carbides” or of the type “hardened by solid solution”.
  • the masking device for a color display cathode ray tube flat screen shown in Figure 1 includes a shadow mask 1 consisting of a sheet pierced with a plurality of holes 2, and a support frame 3 comprising lateral uprights 4 (only one visible in the figure) and end uprights 5 and 5 '.
  • the shadow mask 1 is fixed for example by welding to the upper edges 6 and 6 'of the end posts 5 and 5'.
  • the support frame 3 is subjected to compression forces (small arrows in Figure 1) intended to generate an elastic deformation which reduces the distance between the 5 and 5 'end posts, and the shadow mask is subjected to tensile forces (large arrows in Figure 1) intended to generate an elastic elongation deformation.
  • compression forces small arrows in Figure 1
  • tensile forces large arrows in Figure 1
  • the shadow mask is then fixed by welding to the support frame and the compression and tensile forces are deleted.
  • elastic deformations of the support frame and the shadow mask remain, so that the shadow mask remains subject to voltage.
  • the shadow mask must be made of an Fe-Ni alloy having an average coefficient of thermal expansion between 20 ° C and 150 ° C ( ⁇ 20-150 ) less than 3x10 -6 / K so as to be insensitive to local heating when the cathode ray tube is in service.
  • the frame must be made of a hardened Fe-Ni alloy having an elastic limit Rp0.2 at 20 ° C greater than 700 MPa so as to be able to withstand the tensioning forces of the shadow mask.
  • this alloy must have an average coefficient of thermal expansion between 20 ° C and 150 ° C ( ⁇ 20-150 ) greater than that of the alloy of which the shadow mask is made, so as to avoid relaxing the shadow mask in the event of heating, but this coefficient must nevertheless remain lower than 5 ⁇ 10 -6 / K in order to avoid generating excessive overvoltages in the shadow mask.
  • the average coefficient of expansion between 20 ° C and any higher temperature T at 350 ° C, or better higher than 300 ° C, ⁇ 20-T , of the alloy of which the frame is made must be less than the corresponding average coefficient of thermal expansion of the alloy of which the shadow mask is made. Indeed, if this is so, at high temperature, the dimensions of the shadow mask will be more increased than those of the frame and it will result therefrom that the tensions exerted on the shadow mask will be released; there will be little or no creep.
  • the frame can be made of a hardened Fe-Ni alloy of the "hardened ⁇ '" type, the chemical composition of which comprises, by weight: 40.5% ⁇ Ni + Co + Cu ⁇ 43.5% 0% ⁇ Co ⁇ 5% 0% ⁇ Cu ⁇ 3% 1.5% ⁇ Ti ⁇ 3.5% 0.05% ⁇ Al ⁇ 1% C ⁇ 0.05% If ⁇ 0.5% Mn ⁇ 0.5% S ⁇ 0.01% P ⁇ 0.02% the remainder being iron and impurities resulting from processing.
  • the elements Co and Cu are not essential and may be trace or even absent. The same is true of the elements C, Si, Mn, S and P.
  • the shadow mask can then be made of an Fe-Ni alloy, the composition of which comprises, by weight: 32% ⁇ Ni + Co + Cu ⁇ 37% 0% ⁇ Co ⁇ 5.5% 0% ⁇ Cu ⁇ 2% 0% ⁇ Nb + Ta + Mo + W + Zr ⁇ 2% 0 ⁇ Mn ⁇ 0.5% If ⁇ 0.2% C ⁇ 0.02% S ⁇ 0.01% P ⁇ 0.02% The rest being iron and impurities resulting from processing.
  • the elements Co and Cu are not essential and may be trace or even absent. The same is true of the elements C, Si, Mn, S and P.
  • the elements Nb, Ta, Mo, W and Zr are not essential, and may be trace or even absent. However, in quantity significant, i.e. when the sum of their contents is greater than 0.2% approximately, these elements increase ia creep resistance which is favorable since this reduces the risks caused by high temperature heating.
  • a Fe-Ni alloy of the “hardened ⁇ '” type can be used for the frame Fe-42.5Ni-2.6Ti-0.2Al (approximately 42.5% nickel, 2.6 % titanium and 0.2% aluminum (for the main elements), and an Fe-Ni alloy of the Fe-34.7Ni type for the shadow mask.
  • T 1 is equal to 225 ° C. Therefore, the shadow mask has a satisfactory tension and flatness after integration into the cathode ray tube, including for large screens whose diagonals are 68cm, 80cm, 90cm, or even more.
  • the shadow mask although having a satisfactory tension, may have undulations after integration into the cathode ray tube, especially when the screens are large. Indeed, the risk of ripple is all the more important as the screens are large. For frames that are not too large (diagonal less than 76 cm), this solution can give satisfactory results, although this is not always with good reliability due to the dispersions inherent in any industrial production.
  • the hardened Fe-Ni alloy of which the support frame is made up can be an FeNi alloy of the "hardened ⁇ '" type, the chemical composition of which comprises, by weight: 43.5% ⁇ Ni + Co + Cu ⁇ 45.5% 0% ⁇ Co ⁇ 5% 0% ⁇ Cu ⁇ 3% 1.5% ⁇ Ti ⁇ 3.5% 0.05% ⁇ Al ⁇ 1% C ⁇ 0.05%
  • the Fe-Ni alloy of which the shadow mask is made can be an Fe-Ni alloy, the composition of which comprises, by weight: 35.5% ⁇ Ni + Co + Cu ⁇ 37% 0% ⁇ Co ⁇ 5.5% 0% ⁇ Cu ⁇ 2% 0 ⁇ Mn ⁇ 0.5%
  • ⁇ 0.2% C ⁇ 0.02% S ⁇ 0.01% P ⁇ 0.02% The rest being iron and impurities resulting from processing.
  • the frame is made of an Fe-44.1Ni-2.6Ti-0.2Al alloy which has an elastic limit Rp0.2 at 20 ° C in the upper hardened state. at 700 MPa, and the shadow mask is made of Fe-36Ni (classic INVAR® alloy).
  • T 1 is equal to 300 ° C.
  • the shadow mask has a satisfactory tension and flatness after integration into the cathode ray tube, including for large screens.
  • the frame is always made of Fe-Ni alloy FeNi of the “hardened ⁇ '” type, but it can also be made of hardened Fe-Ni alloy of "hardened carbide” type, “hardened beryllium” type or “solution hardened” solid ”.
  • composition of an alloy of the “hardened carbides” type comprises, by weight: 36% ⁇ Ni + Co + Cu ⁇ 40% 0% ⁇ Co ⁇ 5% 0% ⁇ Cu ⁇ 3% 1.6% ⁇ Mo ⁇ 2.8% 0.4% ⁇ Cr ⁇ 1.5% 0.15% ⁇ C ⁇ 0.35% If ⁇ 0.5% Mn ⁇ 0.5% S ⁇ 0.01% P ⁇ 0.02% the remainder being iron and impurities resulting from processing.
  • composition of an alloy of the “hardened beryllium” type comprises, by weight: 34% ⁇ Ni + Co + Cu ⁇ 38% 0% ⁇ Co ⁇ 5% 0% ⁇ Cu ⁇ 3% 0.15% ⁇ Be ⁇ 1% C ⁇ 0.05% If ⁇ 0.5% Mn ⁇ 1% S ⁇ 0.01% P ⁇ 0.02% the remainder being iron and impurities resulting from processing.
  • composition of an alloy of the “hardened by solid solution” type comprises, by weight: 38% ⁇ Ni + Co + Cu ⁇ 42% 0% ⁇ Co ⁇ 5% 0% ⁇ Cu ⁇ 3% 1% ⁇ Nb ⁇ 4% C ⁇ 0.05% If ⁇ 0.5% Mn ⁇ 0.5% S ⁇ 0.01% P ⁇ 0.02% the remainder being iron and impurities resulting from processing.
  • Fe-Ni alloy of the “hardened ⁇ '” type presents advantages over alloys such as “hardened carbides”, “hardened beryllium” or “Cured by solid solution”.
  • the alloy "hardened ⁇ '" is used in the softened state to form and weld the frame, and the hardening heat treatment is carried out on the finished frame. he on the one hand, the shaping operations are easy to perform and the welds are hardened by the hardening treatment.
  • the other hardened alloys must be used in the hardened state (before shaping and before welding). It follows on the one hand that the operations of setting shaped are more difficult to achieve and on the other hand that the welds are softened by welding heat.

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  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
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  • Organic Chemistry (AREA)
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Abstract

A masking device for a cathode tube for a flat colour visual display screen, of the type comprising a support frame and a flat shadow mask subjected to a voltage at ambient temperature is characterised in that the support frame is made of hardened Fe-Ni alloy with a thermal dilation coefficient of 5 asterisk 10<-6>/K between 20 and 150oC and a limit of elasticity at 20oC greater than 700 Mpa and the flat shadow mask is made of Fe-Ni alloy with thermal dilation coefficient of less than 3 asterisk 10<-6>/K. The Fe-Ni alloys are chosen so that below a temperature (T1) the average dilation coefficient between 20oC and the temperature (T1) of the Fe-Ni alloy of the support frame is greater than that of the shadow mask and above a temperature (T1) the average dilation coefficient between 20oC and the temperature (T1) of the Fe-Ni alloy of the support frame is less than that of the shadow mask, where the temperature (T1) is less than 350oC and preferably less than 300oC. An Independent claim is included for a shadow mask made from a Fe-Ni alloy.

Description

La présente invention concerne un dispositif de masquage pour tube cathodique de visualisation en couleur à écran plat, du type comprenant un cadre support pour masque d'ombre tendu et un masque d'ombre tendu monté sur le cadre support.The present invention relates to a masking device for a tube cathode color display flat screen, of the type comprising a frame support for a stretched shadow mask and a stretched shadow mask mounted on the support frame.

Les tubes cathodiques de visualisation en couleur comportent, de façon connue, un écran de visualisation muni de photophores, un canon à électrons produisant 3 faisceaux d'électrons et un dispositif de masquage, constitué d'un masque d'ombre monté sur un cadre support, disposé en regard de l'écran de visualisation et destiné à assurer une bonne qualité de l'image visualisée. Le masque d'ombre est constitué d'une feuille métallique percée d'une pluralité de trous ou de fentes à travers lesquels les 3 faisceaux d'électrons passent pour aller exciter les photophores disposés sur l'écran. La qualité de l'image obtenue est d'autant meilleure que l'alignement entre les photophores, les trous du masque d'ombre et les faisceaux d'électrons est précis. Lorsque le tube de visualisation est en fonctionnement, une partie significative des faisceaux d'électrons est interceptée par le masque d'ombre, ce qui engendre des échauffements locaux de celui-ci pouvant le déformer et donc détériorer la qualité de l'image visualisée. De plus, la qualité de l'image peut également être détériorée par les vibrations du masque d'ombre provoquées par des sources de vibration diverses. Pour obtenir des images de bonne qualité, le masque d'ombre doit d'une part, être peu sensible aux échauffements locaux, d'autre part, avoir une fréquence propre de vibration suffisamment élevée pour que l'amplitude de ces vibrations ne perturbe pas la couleur des images par un désalignement des faisceaux d'électrons, des trous du masque d'ombre et des photophores.Color display cathode ray tubes have, so known, a display screen provided with photophores, an electron gun producing 3 electron beams and a masking device, consisting of a shadow mask mounted on a support frame, placed opposite the screen of display and intended to ensure good quality of the image viewed. The shadow mask consists of a metal sheet pierced with a plurality of holes or slits through which the 3 electron beams pass to excite the photophores arranged on the screen. The quality of the image obtained is all the more better than the alignment between the lanterns, the holes in the shadow mask and the electron beams are precise. When the viewing tube is in functioning, a significant part of the electron beams is intercepted by the shadow mask, which generates local heating of it which can distort it and therefore deteriorate the quality of the displayed image. In addition, the quality of the image may also be deteriorated by the vibrations of the shadow mask caused by various sources of vibration. To obtain images of good quality, the shadow mask must on the one hand be not very sensitive to local heating, on the other hand, have a natural frequency of vibration high enough that the amplitude of these vibrations does not disturb the color of images by misalignment of electron beams, holes in the shadow mask and tealight holders.

Lorsque l'écran de visualisation est bombé, le masque d'ombre a une forme qui épouse celle de l'écran, et les problèmes de sensibilité aux échauffements locaux et de vibration sont résolus en réalisant le masque d'ombre par emboutissage d'une feuille en alliage Fe-Ni à très faible coefficient de dilatation percée de trous. Le masque d'ombre est simplement soudé sur un cadre support qui n'exerce aucun effort sur le masque d'ombre. Le cadre peut donc être léger, ce qui présente des avantages. When the viewing screen is curved, the shadow mask has a shape which matches that of the screen, and the problems of sensitivity to overheating and vibration are resolved by making the shadow mask by stamping a sheet of Fe-Ni alloy with a very low coefficient of expansion pierced with holes. The shadow mask is simply welded to a support frame which exerts no effort on the shadow mask. The frame can therefore be light, which presents benefits.

Lorsque l'écran de visualisation est plat, le masque d'ombre peut être une feuille non emboutie fixée par exemple par soudage sur un cadre support préalablement comprimé qui exerce ensuite une tension sur le masque d'ombre. Le masque d'ombre est alors dit « tendu ». La tension du masque d'ombre est destinée, d'une part à résoudre le problème de la sensibilité aux échauffements locaux, et d'autre part à augmenter la fréquence propre de vibration du masque d'ombre pour atténuer l'amplitude de ces vibrations. Cette solution suppose notamment l'utilisation d'un matériau dont les caractéristiques permettent de maintenir une tension suffisante dans le domaine de température de fonctionnement du tube cathodique (approximativement 100°C), et cela après un chauffage à environ 600°C lors du procédé de fabrication du tube cathodique. En effet le masque d'ombre monté tendu sur son cadre support est chauffé une première fois aux environs de 600°C pour provoquer une oxydation appelée « blackening», puis, une deuxième fois au voisinage de 450°C, après montage de l'ensemble dans le tube cathodique, lors du scellement de la dalle-écran sur le cône de verre et enfin une troisième fois au voisinage de 380°C lors de la mise sous vide du tube cathodique. Ces chauffages peuvent provoquer un fluage du masque d'ombre et de son cadre qui peut détendre le masque d'ombre.When the display screen is flat, the shadow mask can be a sheet not stamped fixed for example by welding on a support frame previously compressed which then exerts a tension on the shadow mask. The shadow mask is then said to be "stretched". The tension of the shadow mask is intended, on the one hand to solve the problem of sensitivity to local heating, and on the other hand to increase the natural frequency of vibration of the shadow mask for attenuate the amplitude of these vibrations. This solution requires in particular the use of a material whose characteristics make it possible to maintain a tension sufficient in the operating temperature range of the cathode ray tube (approximately 100 ° C), and this after heating to approximately 600 ° C during of the cathode ray tube manufacturing process. Indeed the mounted shadow mask stretched on its support frame is heated for the first time to around 600 ° C to cause an oxidation called "blackening", then a second time at around 450 ° C, after assembly of the assembly in the cathode ray tube, during sealing of the screen slab on the glass cone and finally a third time at around 380 ° C when vacuuming the cathode ray tube. These heaters may cause the shadow mask and its frame to creep which can relax the shadow mask.

Pour fabriquer un masque d'ombre tendu et son cadre support, on a proposé d'utiliser un acier faiblement allié (c'est-à-dire, contenant, en général, moins de 5% d'éléments d'alliage). Mais, le coefficient de dilatation thermique de cet acier étant élevé, la tension du masque d'ombre doit être supérieure à 200 MPa pour éviter les déformations dues aux échauffements locaux. Cette solution conduit à un cadre lourd, dont le poids peut atteindre, voire dépasser, 6 kg.To make a stretched shadow mask and its support frame, we proposed using low alloy steel (i.e. containing, in general, less than 5% alloying elements). However, the coefficient of thermal expansion of this steel being high, the shade mask tension must be higher than 200 MPa to avoid deformations due to local heating. This solution leads to a framework heavy, weighing 6 kg or more.

Pour fabriquer un masque d'ombre tendu et son cadre support, on a également proposé de réaliser le masque d'ombre en alliage Fe-Ni à faible coefficient de dilatation et le cadre en acier. Mais, il est alors nécessaire de prévoir des moyens pour éviter de provoquer des surtensions du masque d'ombre pendant les échauffements à 600°C, faute de quoi, le masque d'ombre se déchire pendant cette opération.To make a stretched shadow mask and its support frame, we have also proposed to make the shadow mask in low-Fe-Ni alloy coefficient of expansion and the steel frame. But, it is then necessary to plan means to avoid causing overvoltage of the shadow mask during overheating at 600 ° C, otherwise the shadow mask tears during this operation.

Pour fabriquer un masque d'ombre tendu et son cadre support, on a aussi proposé de réaliser le masque d'ombre et le cadre support en alliages Fe-Ni à faible coefficient de dilatation, l'alliage Fe-Ni du cadre support pouvant être identique ou différent de l'alliage Fe-Ni du masque d'ombre. Cette solution peut engendrer des défauts au niveau du masque d'ombre, ces défauts étant visibles après le chauffage à 600°C. En effet, le cadre support, de forme généralement rectangulaire, comporte deux montants d'extrémité sur lesquels le masque d'ombre est fixé et deux montants latéraux qui assurent le maintien de l'écartement des montants d'extrémité. Le masque d'ombre, également de forme généralement rectangulaire, est fixé aux montants d'extrémité, généralement par soudage, le long de deux de ses côtés opposés. En tout état de cause, la tension exercée sur le masque d'ombre dans le sens longitudinal engendre une tension dans le sens transversal. Pendant le chauffage à haute température, ces tensions peuvent engendrer des phénomènes de fluage qui, du fait des trous ou des fentes que comporte le masque d'ombre, peuvent engendrer un allongement dans le sens transversal du masque d'ombre. Si lors du chauffage à 600°C, les montants d'extrémité du cadre support se dilatent autant ou plus que le masque d'ombre, la tension initiale dans le sens transversal sera conservée ou accentuée. Après retour à la température ambiante, les montants d'extrémité du cadre support retrouvent leur dimension d'origine, alors que le masque d'ombre a une largeur légèrement augmentée du fait du fluage. Ce phénomène peut conduire à des ondulations du masque d'ombre le rendant inutilisable. Ce défaut qui est d'autant plus important que le masque d'ombre est de grande dimension, peut être aggravé par le fait qu'au refroidissement après le maintien à 600°C, le masque d'ombre se refroidit plus vite que le cadre.To make a stretched shadow mask and its support frame, we also proposed to make the shadow mask and the support frame in low Fe-Ni alloys coefficient of expansion, the Fe-Ni alloy of the support frame being able to be identical or different from the Fe-Ni alloy of the shadow mask. This solution can cause defects in the shadow mask, these defects being visible after heating at 600 ° C. Indeed, the support frame, of generally rectangular shape, comprises two end posts on which the shadow mask is fixed and two posts side which maintain the spacing of the end posts. The shadow mask, also generally rectangular in shape, is attached to the end posts, usually by welding, along two of its sides opposites. In any event, the tension exerted on the shadow mask in the longitudinal direction creates tension in the transverse direction. During the heating at high temperature, these voltages can cause phenomena creep which, due to the holes or slits in the shadow mask, can cause an elongation in the transverse direction of the shadow mask. Yes when heating to 600 ° C, the end posts of the support frame expand as much or more than the shadow mask, the initial tension in the transverse direction will be kept or enhanced. After returning to room temperature, the amounts of the support frame return to their original size, while the shadow mask has a slightly increased width due to creep. This phenomenon can lead to ripples of the shadow mask making it unusable. This defect which is all the more important as the shadow mask is large dimension, may be aggravated by the fact that after cooling after maintained at 600 ° C, the shadow mask cools faster than the frame.

Le but de la présente invention est de remédier à ces inconvénients en proposant un moyen pour fabriquer un masque d'ombre tendu et son cadre support peu sensibles aux échauffements locaux, ayant une fréquence propre de vibration convenable et ayant une bonne planéité après les chauffages à haute température résultant des opérations de fabrication.The object of the present invention is to remedy these drawbacks by proposing a means for manufacturing a stretched shadow mask and its support frame not very sensitive to local heating, having a natural frequency of vibration suitable and having good flatness after high temperature heating resulting from manufacturing operations.

A cet effet, l'invention a pour objet un dispositif de masquage pour tube cathodique de visualisation en couleur à écran plat, du type comprenant un cadre support pour masque d'ombre tendu et un masque d'ombre tendu monté sur le cadre support de façon à être soumis à une tension à la température ambiante. Le cadre support est en alliage Fe-Ni durci ayant un coefficient de dilatation thermique entre 20°C et 150°C inférieur à 5x10-6/K et une limite d'élasticité Rp0,2 à 20°C supérieure à 700 MPa. Le masque d'ombre tendu est en alliage Fe-Ni ayant un coefficient de dilatation thermique entre 20°C et 150°C inférieur à 3x10-6/K. L'alliage Fe-Ni durci dont est constitué le cadre support et l'alliage Fe-Ni dont est constitué le masque d'ombre sont choisis de telle sorte que, en dessous d'une température T1, le coefficient de dilatation moyen α20-T, entre 20°C et la température T, de l'alliage Fe-Ni durci dont est constitué le cadre support est supérieur au coefficient de dilatation moyen α20-T, entre 20°C et la température T, de l'alliage Fe-Ni dont est constitué le masque d'ombre ; au dessus de ladite température T1, le coefficient de dilatation moyen α20-T, entre 20°C et la température T, de l'alliage Fe-Ni durci dont est constitué le cadre support est inférieur au coefficient de dilatation moyen α20-T, entre 20°C et la température T, de l'alliage Fe-Ni dont est constitué le masque d'ombre ; ladite température T1 est inférieure à 350°C, et de préférence inférieure à 300°C.To this end, the subject of the invention is a masking device for a cathode ray tube for color display on a flat screen, of the type comprising a support frame for a stretched shadow mask and a stretched shadow mask mounted on the support frame. so as to be subjected to a voltage at room temperature. The support frame is made of hardened Fe-Ni alloy having a coefficient of thermal expansion between 20 ° C and 150 ° C less than 5x10 -6 / K and an elastic limit Rp0.2 at 20 ° C greater than 700 MPa. The stretched shadow mask is made of Fe-Ni alloy having a coefficient of thermal expansion between 20 ° C and 150 ° C less than 3x10 -6 / K. The hardened Fe-Ni alloy of which the support frame is made and the Fe-Ni alloy of which the shadow mask is made are chosen so that, below a temperature T 1 , the mean coefficient of expansion α 20-T , between 20 ° C and temperature T, of the hardened Fe-Ni alloy of which the support frame is made is greater than the average coefficient of expansion α 20-T , between 20 ° C and temperature T, of l 'Fe-Ni alloy of which the shadow mask is made; above said temperature T 1 , the average coefficient of expansion α 20-T , between 20 ° C and the temperature T, of the hardened Fe-Ni alloy of which the support frame is made is lower than the average coefficient of expansion α 20 -T , between 20 ° C and temperature T, of the Fe-Ni alloy from which the shadow mask is made; said temperature T 1 is less than 350 ° C, and preferably less than 300 ° C.

De préférence, l'alliage Fe-Ni durci dont est constitué le cadre support est un alliage FeNi du type « durci γ' » dont la composition chimique comprend, en poids : 40,5% ≤ Ni + Co + Cu ≤ 43,5% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1,5% ≤ Ti ≤ 3,5% 0,05% ≤ Al ≤ 1% C ≤ 0,05% Si ≤ 0,5% Mn ≤ 0,5% S ≤ 0,01% P ≤ 0,02% le reste étant du fer et des impuretés résultant de l'élaboration,
et l'alliage Fe-Ni dont est constitué le masque d'ombre est un alliage Fe-Ni dont la composition comprend, en poids : 32% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5,5% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr ≤ 2% 0 ≤ Mn ≤ 0,5% Si < 0,2% C < 0,02% S < 0,01% P < 0,02% Le reste étant du fer et des impuretés résultant de l'élaboration.Preferably, the hardened Fe-Ni alloy of which the support frame is made up is an FeNi alloy of the "hardened γ '" type, the chemical composition of which comprises, by weight: 40.5% ≤ Ni + Co + Cu ≤ 43.5% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1.5% ≤ Ti ≤ 3.5% 0.05% ≤ Al ≤ 1% C ≤ 0.05% If ≤ 0.5% Mn ≤ 0.5% S ≤ 0.01% P ≤ 0.02% the rest being iron and impurities resulting from the production,
and the Fe-Ni alloy of which the shadow mask is made is an Fe-Ni alloy, the composition of which comprises, by weight: 32% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5.5% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr ≤ 2% 0 ≤ Mn ≤ 0.5% If <0.2% C <0.02% S <0.01% P <0.02% The rest being iron and impurities resulting from processing.

La composition chimique de l'alliage Fe-Ni dont est constitué le masque d'ombre peut, par exemple, être telle que : 32% ≤ Ni + Co + Cu ≤ 35,5% 0% ≤ Co ≤ 4% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr ≤ 0,2% The chemical composition of the Fe-Ni alloy from which the shadow mask is made can, for example, be such that: 32% ≤ Ni + Co + Cu ≤ 35.5% 0% ≤ Co ≤ 4% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr ≤ 0.2%

La composition chimique de l'alliage Fe-Ni dont est constitué le masque d'ombre peut, également, être telle que : 33,5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5,5% 0% ≤ Cu ≤ 2% 0,2% ≤ Nb + Ta + Mo + W + Zr ≤ 2% The chemical composition of the Fe-Ni alloy from which the shadow mask is made can also be such that: 33.5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5.5% 0% ≤ Cu ≤ 2% 0.2% ≤ Nb + Ta + Mo + W + Zr ≤ 2%

Dans un autre mode de réalisation, l'alliage Fe-Ni durci dont est constitué le cadre support peut être un alliage FeNi du type « durci γ' » dont la composition chimique comprend, en poids : 43,5% ≤ Ni + Co + Cu ≤ 45,5% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1,5% ≤ Ti ≤ 3,5% 0,05 % ≤ Al ≤ 1% C ≤ 0,05% Si ≤ 0,5% Mn ≤ 0,5% S ≤ 0,01% P ≤ 0,02% le reste étant du fer et des impuretés résultant de l'élaboration, et l'alliage Fe-Ni dont est constitué le masque d'ombre peut être un alliage Fe-Ni dont la composition comprend, en poids : 35,5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5,5% 0% ≤ Cu ≤ 2% 0 ≤ Mn ≤ 0,5% Si < 0,2% C < 0,02% S < 0,01% P < 0,02% Le reste étant du fer et des impuretés résultant de l'élaboration.In another embodiment, the hardened Fe-Ni alloy of which the support frame is made up can be a FeNi alloy of the “hardened γ '” type, the chemical composition of which comprises, by weight: 43.5% ≤ Ni + Co + Cu ≤ 45.5% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1.5% ≤ Ti ≤ 3.5% 0.05% ≤ Al ≤ 1% C ≤ 0.05% If ≤ 0.5% Mn ≤ 0.5% S ≤ 0.01% P ≤ 0.02% the remainder being iron and impurities resulting from the preparation, and the Fe-Ni alloy of which the shadow mask is made up can be an Fe-Ni alloy, the composition of which comprises, by weight: 35.5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5.5% 0% ≤ Cu ≤ 2% 0 ≤ Mn ≤ 0.5% If <0.2% C <0.02% S <0.01% P <0.02% The rest being iron and impurities resulting from processing.

L'invention concerne également un masque d'ombre tendu constitué d'un alliage Fe-Ni dont la composition chimique comprend, en poids : 32% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5,5% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr ≤ 2% 0 ≤ Mn ≤ 0,5% Si < 0,2% C < 0,02% S < 0,01% P < 0,02% Le reste étant du fer et des impuretés résultant de l'élaboration.The invention also relates to a stretched shadow mask consisting of an Fe-Ni alloy, the chemical composition of which comprises, by weight: 32% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5.5% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr ≤ 2% 0 ≤ Mn ≤ 0.5% If <0.2% C <0.02% S <0.01% P <0.02% The rest being iron and impurities resulting from processing.

La composition chimique de l'alliage Fe-Ni dont est constitué le masque d'ombre peut, de préférence, être telle que: 32% ≤ Ni + Co + Cu ≤ 35,5% 0% ≤ Co ≤ 4% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr ≤ 0,2% The chemical composition of the Fe-Ni alloy from which the shadow mask is made may preferably be such that: 32% ≤ Ni + Co + Cu ≤ 35.5% 0% ≤ Co ≤ 4% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr ≤ 0.2%

La composition chimique de l'alliage Fe-Ni dont est constitué le masque d'ombre peut également être telle que: 33,5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5,5% 0% ≤ Cu ≤ 2% 0,2% ≤ Nb + Ta + Mo + W + Zr ≤ 2% The chemical composition of the Fe-Ni alloy from which the shadow mask is made can also be such that: 33.5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5.5% 0% ≤ Cu ≤ 2% 0.2% ≤ Nb + Ta + Mo + W + Zr ≤ 2%

Enfin, le cadre peut aussi être constitué d'un alliage Fe-Ni durci du type « durci béryllium », « durci carbures » ou du type « durci par solution solide ».Finally, the frame can also be made of a hardened Fe-Ni alloy of the type "Hardened beryllium", "hardened carbides" or of the type "hardened by solid solution".

L'invention va maintenant être décrite plus en détails et illustrée par des exemples, mais de façon non limitative, en regard des figures annexées dans lesquelles :

  • la figure 1 représente en perspective, de façon schématique, un dispositif de masquage pour tube cathodique de visualisation en couleur à écran plat,
The invention will now be described in more detail and illustrated by examples, but not limited to, with reference to the appended figures in which:
  • FIG. 1 shows in perspective, schematically, a masking device for a cathode ray tube for color display on a flat screen,

Le dispositif de masquage pour tube cathodique de visualisation en couleur à écran plat représenté à la figure 1 comprend un masque d'ombre 1 constitué d'une feuille percée d'une pluralité de trous 2, et un cadre support 3 comportant des montants latéraux 4 (un seul visible sur la figure) et des montants d'extrémité 5 et 5'. Le masque d'ombre 1 est fixé par exemple par soudage sur les arêtes supérieures 6 et 6' des montants d'extrémité 5 et 5'.The masking device for a color display cathode ray tube flat screen shown in Figure 1 includes a shadow mask 1 consisting of a sheet pierced with a plurality of holes 2, and a support frame 3 comprising lateral uprights 4 (only one visible in the figure) and end uprights 5 and 5 '. The shadow mask 1 is fixed for example by welding to the upper edges 6 and 6 'of the end posts 5 and 5'.

Lors du montage, le cadre support 3 est soumis à des efforts de compression (petites flèches sur la figure 1) destinés à engendrer une déformation élastique qui réduit l'écartement des montants d'extrémité 5 et 5', et le masque d'ombre est soumis à des efforts de traction (grosses flèches sur la figure 1) destinés à engendrer une déformation élastique d'allongement. Le masque d'ombre est alors fixé par soudage sur le cadre support et les efforts de compression et de traction sont supprimés. Cependant, des déformations élastiques du cadre support et du masque d'ombre subsistent, si bien que le masque d'ombre reste soumis à une tension.During assembly, the support frame 3 is subjected to compression forces (small arrows in Figure 1) intended to generate an elastic deformation which reduces the distance between the 5 and 5 'end posts, and the shadow mask is subjected to tensile forces (large arrows in Figure 1) intended to generate an elastic elongation deformation. The shadow mask is then fixed by welding to the support frame and the compression and tensile forces are deleted. However, elastic deformations of the support frame and the shadow mask remain, so that the shadow mask remains subject to voltage.

Le dispositif constitué du cadre support et du masque d'ombre est alors porté à une température d'environ 600°C dans une atmosphère légèrement oxydante, de façon à créer en surface une fine couche d'oxyde. Cette opération est appelée communément « blackening ». Puis le dispositif est monté dans le tube cathodique et celui-ci est scellé à une température voisine de 450°C pendant environ 1 heure. Enfin, le tube cathodique est mis sous vide, et au cours de cette opération , il est chauffé au voisinage de 380°C. Lors de ces différents chauffages, et en particulier lors du chauffage au voisinage de 600°C, le cadre et le masque d'ombre se dilatent. Lorsque le cadre et le masque d'ombre sont constitués de matériaux différents, les dilatations du cadre et du masque d'ombre sont différentes. En particulier, si, à 600°C, la dilatation du cadre est supérieure à la dilatation du masque, la différence de dilatation engendre une tension supplémentaire du masque d'ombre qui peut engendrer un fluage du masque d'ombre. Ce fluage, si il est trop important, a un double effet :

  • dans le sens longitudinal, c'est à dire parallèlement aux montant latéraux, le fluage augmente la longueur du masque d'ombre à la température ambiante ce qui en diminue la tension ; un faible fluage est favorable, voir souhaité car cela permet de symétriser la répartition en largeur des contraintes de tension. Mais, si ce fluage est trop important, la tension du masque d'ombre devient trop faible, et de ce fait, les fréquencespropresde vibration du masque d'ombre deviennent trop faibles.
  • dans le sens transversal, c'est à dire parallèlement aux montants d'extrémité, le fluage augmente la largeur du masque d'ombre à la température ambiante qui devient supérieure à la longueur des montants d'extrémité sur lesquels il est fixé par soudage ; il en résulte la formation d'ondulations. Ce phénomène est d'autant plus marqué que le masque d'ombre est percé d'une multitude de trous ou de fentes qui en diminuent la section effective. En particulier, entre les fentes, la section est évidemment réduite et donc la contrainte de tension est augmentée, il en résulte des risque de fluage beaucoup plus importants.
The device consisting of the support frame and the shadow mask is then brought to a temperature of around 600 ° C. in a slightly oxidizing atmosphere, so as to create a thin layer of oxide on the surface. This operation is commonly called "blackening". Then the device is mounted in the cathode ray tube and the latter is sealed at a temperature in the region of 450 ° C for approximately 1 hour. Finally, the cathode ray tube is placed under vacuum, and during this operation, it is heated in the vicinity of 380 ° C. During these different heatings, and in particular when heating in the vicinity of 600 ° C., the frame and the shadow mask expand. When the frame and the shadow mask are made of different materials, the expansions of the frame and the shadow mask are different. In particular, if, at 600 ° C., the expansion of the frame is greater than the expansion of the mask, the difference in expansion generates an additional tension of the shadow mask which can cause creep of the shadow mask. This creep, if it is too large, has a double effect:
  • in the longitudinal direction, that is to say parallel to the lateral uprights, the creep increases the length of the shadow mask at ambient temperature which reduces its tension; a low creep is favorable, or even desired, as this allows the width distribution of the stresses to be symmetrical. However, if this creep is too great, the tension of the shadow mask becomes too low, and therefore the clean vibration frequencies of the shadow mask become too low.
  • in the transverse direction, that is to say parallel to the end uprights, the creep increases the width of the shadow mask at ambient temperature which becomes greater than the length of the end uprights to which it is fixed by welding; this results in the formation of ripples. This phenomenon is all the more marked as the shadow mask is pierced with a multitude of holes or slits which reduce the effective section. In particular, between the slots, the section is obviously reduced and therefore the tension stress is increased, this results in a much greater risk of creep.

Les inventeurs ont constaté que ces deux inconvénients pouvaient être évités si on utilisait pour réaliser le masque d'ombre et le cadre support, des alliages choisis comme cela va être indiqué ci après.The inventors have found that these two disadvantages can be avoided if we used to make the shadow mask and the support frame, selected alloys as will be indicated below.

Le masque d'ombre doit être constitué d'un alliage Fe-Ni ayant un coefficient de dilatation thermique moyen entre 20°C et 150°C (α20-150) inférieur à 3x10-6/K de façon à être peu sensible aux échauffements locaux lorsque le tube cathodique est en service.The shadow mask must be made of an Fe-Ni alloy having an average coefficient of thermal expansion between 20 ° C and 150 ° C (α 20-150 ) less than 3x10 -6 / K so as to be insensitive to local heating when the cathode ray tube is in service.

Le cadré doit être constitué d'un alliage Fe-Ni durci ayant une limite d'élasticité Rp0,2 à 20°C supérieure à 700 MPa de façon a pouvoir supporter les efforts de tension du masque d'ombre. De plus, cet alliage doit avoir un coefficient de dilatation thermique moyen entre 20°C et 150°C (α20-150) supérieur à celui de l'alliage dont est constitué le masque d'ombre, de façon à éviter de détendre le masque d'ombre en cas d'échauffement, mais ce coefficient doit néanmoins rester inférieur à 5x10-6/K afin d'éviter d'engendrer des surtensions trop importantes dans le masque d'ombre.The frame must be made of a hardened Fe-Ni alloy having an elastic limit Rp0.2 at 20 ° C greater than 700 MPa so as to be able to withstand the tensioning forces of the shadow mask. In addition, this alloy must have an average coefficient of thermal expansion between 20 ° C and 150 ° C (α 20-150 ) greater than that of the alloy of which the shadow mask is made, so as to avoid relaxing the shadow mask in the event of heating, but this coefficient must nevertheless remain lower than 5 × 10 -6 / K in order to avoid generating excessive overvoltages in the shadow mask.

En outre, et pour éviter les inconvénients résultant des chauffages à haute température signalés plus haut, au dessus de 350°C, et mieux, au dessus de 300°C, le coefficient de dilatation moyen entre 20°C et une température T quelconque supérieure à 350°C, ou mieux supérieure à 300°C, α20-T, de l'alliage dont est constitué le cadre doit être inférieur au coefficient de dilatation thermique moyen correspondant de l'alliage dont est constitué le masque d'ombre. En effet, si il en est ainsi, à haute température, les dimensions du masque d'ombre seront plus augmentées que celles du cadre et il en résultera que les tensions exercées sur le masque d'ombre seront relâchées ; il n'y aura pas ou peu de fluage.In addition, and to avoid the drawbacks resulting from the high-temperature heating mentioned above, above 350 ° C, and better still, above 300 ° C, the average coefficient of expansion between 20 ° C and any higher temperature T at 350 ° C, or better higher than 300 ° C, α 20-T , of the alloy of which the frame is made must be less than the corresponding average coefficient of thermal expansion of the alloy of which the shadow mask is made. Indeed, if this is so, at high temperature, the dimensions of the shadow mask will be more increased than those of the frame and it will result therefrom that the tensions exerted on the shadow mask will be released; there will be little or no creep.

L'ensemble des conditions relatives aux coefficients de dilatation peut s'exprimer de façon équivalente comme cela a été fait plus haut, en faisant intervenir une température T1 inférieure à 350°C ou mieux inférieure à 300°C, telle que , pour toute température T :

  • si T < T1, alors α20-Tpour le masque d'ombre < α20-Tpour le cadre (au moins pour T > 20°C),
  • si T > T1, alors α20-Tpour le masque d'ombre > α20-Tpour le cadre (au moins pour T jusqu'à 600°C).
All the conditions relating to the expansion coefficients can be expressed in an equivalent manner as has been done above, by involving a temperature T 1 less than 350 ° C or better still less than 300 ° C, such that, for any temperature T:
  • if T <T1, then α 20-T for the shadow mask <α 20-T for the frame (at least for T> 20 ° C),
  • if T> T1, then α 20-T for the shadow mask> α 20-T for the frame (at least for T up to 600 ° C).

Pour satisfaire ces conditions, le cadre peut être constitué d'un alliage Fe-Ni durci du type « durci γ' » dont la composition chimique comprend, en poids : 40,5% ≤ Ni + Co + Cu ≤ 43,5% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1,5% ≤ Ti ≤ 3,5% 0,05% ≤ Al ≤ 1% C ≤ 0,05% Si ≤ 0,5% Mn ≤ 0,5% S ≤ 0,01% P ≤ 0,02% le reste étant du fer et des impuretés résultant de l'élaboration.To satisfy these conditions, the frame can be made of a hardened Fe-Ni alloy of the "hardened γ '" type, the chemical composition of which comprises, by weight: 40.5% ≤ Ni + Co + Cu ≤ 43.5% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1.5% ≤ Ti ≤ 3.5% 0.05% ≤ Al ≤ 1% C ≤ 0.05% If ≤ 0.5% Mn ≤ 0.5% S ≤ 0.01% P ≤ 0.02% the remainder being iron and impurities resulting from processing.

Dans cet alliage, les éléments Co et Cu ne sont pas indispensables et peuvent être à l'état de traces ou même absents. Il en est de même des éléments C, Si, Mn, S et P.In this alloy, the elements Co and Cu are not essential and may be trace or even absent. The same is true of the elements C, Si, Mn, S and P.

Le masque d'ombre peut alors être constitué d'un alliage Fe-Ni dont la composition comprend, en poids : 32% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5,5% 0% ≤ Cu ≤ 2% 0 % ≤ Nb + Ta + Mo + W + Zr ≤ 2% 0 ≤ Mn ≤ 0,5% Si < 0,2% C < 0,02% S < 0,01% P < 0,02% Le reste étant du fer et des impuretés résultant de l'élaboration.The shadow mask can then be made of an Fe-Ni alloy, the composition of which comprises, by weight: 32% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5.5% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr ≤ 2% 0 ≤ Mn ≤ 0.5% If <0.2% C <0.02% S <0.01% P <0.02% The rest being iron and impurities resulting from processing.

Dans cet alliage, les éléments Co et Cu ne sont pas indispensables et peuvent être à l'état de traces ou même absents. Il en est de même des éléments C, Si, Mn, S et P.In this alloy, the elements Co and Cu are not essential and may be trace or even absent. The same is true of the elements C, Si, Mn, S and P.

De même, les éléments Nb, Ta, Mo, W et Zr ne sont pas indispensables, et peuvent être à l'état de traces ou même absents. Néanmoins, en quantité significative, c'est à dire lorsque la somme de leur teneurs est supérieure à 0,2% environ, ces éléments augmentent ia tenue au fluage ce qui est favorable puisque cela diminue les risques engendrés par les chauffages à haute température.Likewise, the elements Nb, Ta, Mo, W and Zr are not essential, and may be trace or even absent. However, in quantity significant, i.e. when the sum of their contents is greater than 0.2% approximately, these elements increase ia creep resistance which is favorable since this reduces the risks caused by high temperature heating.

Cependant, ces éléments ont une effet sur le coefficient de dilatation, aussi, il est préférable de choisir :

  • soit un alliage dont la composition chimique est telle que : 32% ≤ Ni + Co + Cu ≤ 35,5% 0% ≤ Co ≤ 4% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr < 0,2%
  • soit un alliage dont la composition chimique est telle que: 33,5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5,5% 0% ≤ Cu ≤ 2% 0,2% ≤ Nb + Ta + Mo + W + Zr ≤ 2%
However, these elements have an effect on the coefficient of expansion, so it is better to choose:
  • either an alloy whose chemical composition is such that: 32% ≤ Ni + Co + Cu ≤ 35.5% 0% ≤ Co ≤ 4% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr <0.2%
  • either an alloy whose chemical composition is such that: 33.5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5.5% 0% ≤ Cu ≤ 2% 0.2% ≤ Nb + Ta + Mo + W + Zr ≤ 2%

A titre d'exemple, on peut utiliser pour le cadre, un alliage Fe-Ni du type « durci γ' » Fe-42,5Ni-2,6Ti-0,2Al (environ 42,5% de nickel, 2,6% de titane et 0,2% d'aluminium, pour ce qui est des éléments principaux), et un alliage Fe-Ni du type Fe-34,7Ni pour le masque d'ombre. L'alliage durci a une limite d'élasticité Rp0,2 à 20°C supérieure à 700 MPa à l'état durci, et les coefficients de dilatation moyens sont : α20-T T=50°C T=150°C T=225°C T=300°C T=400°C T=500°C T=600°C Fe-42,5Ni-2,6Ti-0,2Al 3x10-6/K 3,4x10-6/K 4x10-6/K 5,4x10-6/K 7,9x10-6/K 9,5x10-6/K 10,8x10-6/K Fe-34,7Ni 0,8x10-6/K 2x10-6/K 4x10-6/K 6,6x10-6/K 9,1x10-6/K 10x10-6/K 12x10-6/K As an example, a Fe-Ni alloy of the “hardened γ '” type can be used for the frame Fe-42.5Ni-2.6Ti-0.2Al (approximately 42.5% nickel, 2.6 % titanium and 0.2% aluminum (for the main elements), and an Fe-Ni alloy of the Fe-34.7Ni type for the shadow mask. The hardened alloy has an elastic limit Rp0,2 at 20 ° C greater than 700 MPa in the hardened state, and the average coefficients of expansion are: α 20-T T = 50 ° C T = 150 ° C T = 225 ° C T = 300 ° C T = 400 ° C T = 500 ° C T = 600 ° C Fe-42.5Ni-2.6Ti-0.2Al 3x10 -6 / K 3.4x10 -6 / K 4x10 -6 / K 5.4x10 -6 / K 7.9x10 -6 / K 9.5x10 -6 / K 10.8x10 -6 / K Fe-34.7Ni 0.8x10 -6 / K 2x10 -6 / K 4x10 -6 / K 6.6x10 -6 / K 9.1x10 -6 / K 10x10 -6 / K 12x10 -6 / K

Dans ce cas, T1 est égale à 225°C. De ce fait, le masque d'ombre a une tension et une planéité satisfaisante après intégration dans le tube cathodique, y compris pour les écrans de grande dimension dont les diagonales font 68cm, 80cm, 90cm, voire plus.In this case, T 1 is equal to 225 ° C. Therefore, the shadow mask has a satisfactory tension and flatness after integration into the cathode ray tube, including for large screens whose diagonals are 68cm, 80cm, 90cm, or even more.

En utilisant toujours l'alliage Fe-42,5Ni-2,6Ti-0,2Al pour le cadre et l'alliage Fe-36Ni-1,2Nb pour le masque d'ombre, les coefficients de dilatation moyens sont : α20-T T=50°C T=150°C T=225°C T=300°C T=400°C T=500°C T=600°C Fe-42,5Ni-2,6Ti-0,2Al 3x10-6/K 3,4x10-6/K 4x10-6/K 5,4x10-6/K 7,9x10-6/K 9,5x10-6/K 10,8x10-6/K Fe-36Ni-1,2Nb 1,2x10-6/K 2,1x10-6/K 4x10-6/K 6,5x10-6/K 9x10-6/K 10,7x10-6/K 11,9x10-6/K Dans ce cas, T1 est égale à 225°C. De ce fait, le masque d'ombre a une tension et une pianéité satisfaisante après intégration dans le tube cathodique, y compris pour les écrans de grande dimension dont les diagonales font 68cm, 80cm, 90cm, voire plus.Always using the Fe-42.5Ni-2.6Ti-0.2Al alloy for the frame and the Fe-36Ni-1.2Nb alloy for the shadow mask, the mean expansion coefficients are: α 20-T T = 50 ° C T = 150 ° C T = 225 ° C T = 300 ° C T = 400 ° C T = 500 ° C T = 600 ° C Fe-42.5Ni-2.6Ti-0.2Al 3x10 -6 / K 3.4x10 -6 / K 4x10 -6 / K 5.4x10 -6 / K 7.9x10 -6 / K 9.5x10 -6 / K 10.8x10 -6 / K Fe-36Ni-1,2Nb 1.2x10 -6 / K 2.1x10 -6 / K 4x10 -6 / K 6.5x10 -6 / K 9x10 -6 / K 10.7x10 -6 / K 11.9x10 -6 / K In this case, T 1 is equal to 225 ° C. Therefore, the shadow mask has a satisfactory tension and pianity after integration into the cathode ray tube, including for large screens whose diagonals are 68cm, 80cm, 90cm, or even more.

A titre de comparaison, lorsque le cadre est en alliage Fe-42,5Ni-2,6Ti-0,2Al, et le masque d'ombre en Fe-36Ni (alliage INVAR® classique), les coefficients de dilatation sont : α20-T T=50°C T=150°C T=200°C T=300°C T=400°C T=500°C T=600°C Fe-42,5Ni-2,6Ti-0,2Al 3x10-6/K 3,4x10-6/K 3,8x10-6/K 5,4x10-6/K 7,9x10-6/K 9,5x10-6/K 10,8x10-6/K Fe-36Ni 0,8x10-6/K 1,4x10-6/K 2x10-6/K 5x10-6/K 7,8x10-6/K 9,6x10-6/K 11,1x10-6/K Dans ce cas, T1 est égale à environ 440°C. Et on constate que le masque d'ombre bien qu'ayant une tension satisfaisante peut présenter des ondulations après intégration dans le tube cathodique notamment lorsque les écrans sont de grande dimension. En effet, le risque d'ondulation est d'autant plus important que les écrans sont grands. Pour les cadres pas trop grands (diagonale inférieure à 76 cm), cette solution peut donner des résultats satisfaisants, encore que ce ne soit pas toujours avec une bonne fiabilité du fait des dispersions inhérentes à toute production industrielle.For comparison, when the frame is made of Fe-42.5Ni-2.6Ti-0.2Al alloy, and the shadow mask made of Fe-36Ni (classic INVAR® alloy), the expansion coefficients are: α 20-T T = 50 ° C T = 150 ° C T = 200 ° C T = 300 ° C T = 400 ° C T = 500 ° C T = 600 ° C Fe-42.5Ni-2.6Ti-0.2Al 3x10 -6 / K 3.4x10 -6 / K 3.8x10 -6 / K 5.4x10 -6 / K 7.9x10 -6 / K 9.5x10 -6 / K 10.8x10 -6 / K Fe-36Ni 0.8x10 -6 / K 1.4x10 -6 / K 2x10 -6 / K 5x10 -6 / K 7.8x10 -6 / K 9.6x10 -6 / K 11.1x10 -6 / K In this case, T 1 is equal to approximately 440 ° C. And it is noted that the shadow mask, although having a satisfactory tension, may have undulations after integration into the cathode ray tube, especially when the screens are large. Indeed, the risk of ripple is all the more important as the screens are large. For frames that are not too large (diagonal less than 76 cm), this solution can give satisfactory results, although this is not always with good reliability due to the dispersions inherent in any industrial production.

Dans un autre mode de rélisation, l'alliage Fe-Ni durci dont est constitué le cadre support peut être un alliage FeNi du type « durci γ' » dont la composition chimique comprend, en poids : 43,5% ≤ Ni + Co + Cu ≤ 45,5% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1,5% ≤ Ti ≤ 3,5% 0,05% ≤ Al ≤ 1% C ≤ 0,05% Si ≤ 0,5% Mn ≤ 0,5% S ≤ 0,01% P ≤ 0,02% le reste étant du fer et des impuretés résultant de l'élaboration,
et l'alliage Fe-Ni dont est constitué le masque d'ombre peut être un alliage Fe-Ni dont la composition comprend, en poids : 35,5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5,5% 0% ≤ Cu ≤ 2% 0 ≤ Mn ≤ 0,5% Si < 0,2% C < 0,02 % S < 0,01% P < 0,02% Le reste étant du fer et des impuretés résultant de l'élaboration.In another embodiment, the hardened Fe-Ni alloy of which the support frame is made up can be an FeNi alloy of the "hardened γ '" type, the chemical composition of which comprises, by weight: 43.5% ≤ Ni + Co + Cu ≤ 45.5% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1.5% ≤ Ti ≤ 3.5% 0.05% ≤ Al ≤ 1% C ≤ 0.05% If ≤ 0.5% Mn ≤ 0.5% S ≤ 0.01% P ≤ 0.02% the rest being iron and impurities resulting from the production,
and the Fe-Ni alloy of which the shadow mask is made can be an Fe-Ni alloy, the composition of which comprises, by weight: 35.5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5.5% 0% ≤ Cu ≤ 2% 0 ≤ Mn ≤ 0.5% If <0.2% C <0.02% S <0.01% P <0.02% The rest being iron and impurities resulting from processing.

A titre d'exemple de ce mode de réalisation, le cadre est réalisé en alliage Fe-44,1Ni-2,6Ti-0,2Al qui a une limite d'élasticité Rp0,2 à 20°C à l'état durci supérieure à 700MPa, et le masque d'ombre est constitué de Fe-36Ni (alliage INVAR® classique). Dans ce cas, les coefficients de dilatation sont : α20-T T=50°C T=150°C T=200°C T=300°C T=400°C T=500°C T=600°C Fe-44,1Ni-2,6Ti-0,2Al 4,1x10-6/K 4x10-6/K 4,1x10-6/K 5x10-6/K 7,2x10-6/K 9x10-6/K 10,2x10-6/K Fe-36Ni 0,8x10-6/K 1,4x10-6/K 2x10-6/K 5x10-6/K 7,8x10-6/K 9,6x10-6/K 11,1x10-6/K Dans ce cas, T1 est égale à 300°C. De ce fait, le masque d'ombre a une tension et une planéité satisfaisante après intégration dans le tube cathodique, y compris pour les écrans de grande dimension.As an example of this embodiment, the frame is made of an Fe-44.1Ni-2.6Ti-0.2Al alloy which has an elastic limit Rp0.2 at 20 ° C in the upper hardened state. at 700 MPa, and the shadow mask is made of Fe-36Ni (classic INVAR® alloy). In this case, the expansion coefficients are: α 20-T T = 50 ° C T = 150 ° C T = 200 ° C T = 300 ° C T = 400 ° C T = 500 ° C T = 600 ° C Fe-44,1Ni-2,6Ti-0,2Al 4.1x10 -6 / K 4x10 -6 / K 4.1x10 -6 / K 5x10 -6 / K 7.2x10 -6 / K 9x10 -6 / K 10.2x10 -6 / K Fe-36Ni 0.8x10 -6 / K 1.4x10 -6 / K 2x10 -6 / K 5x10 -6 / K 7.8x10 -6 / K 9.6x10 -6 / K 11.1x10 -6 / K In this case, T 1 is equal to 300 ° C. As a result, the shadow mask has a satisfactory tension and flatness after integration into the cathode ray tube, including for large screens.

Dans les exemples décrits ci-dessus, le cadre est toujours en alliage Fe-Ni FeNi du type « durci γ' », mais il peut également être réalisé en alliage Fe-Ni durci du type « durci carbure », du type « durci béryllium » ou du type « durci par solution solide ».In the examples described above, the frame is always made of Fe-Ni alloy FeNi of the “hardened γ '” type, but it can also be made of hardened Fe-Ni alloy of "hardened carbide" type, "hardened beryllium" type or "solution hardened" solid ”.

La composition d'un alliage du type « durci carbures » comprend, en poids: 36% ≤ Ni + Co + Cu ≤ 40% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1,6% ≤ Mo ≤ 2,8% 0,4% ≤ Cr ≤ 1,5% 0,15% ≤ C ≤ 0,35% Si ≤ 0,5% Mn ≤ 0,5% S ≤ 0,01% P ≤ 0,02% le reste étant du fer et des impuretés résultant de l'élaboration.
La composition d'un alliage du type « durci béryllium » comprend, en poids: 34% ≤ Ni + Co + Cu ≤ 38% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 0,15% ≤ Be ≤ 1% C ≤ 0,05% Si ≤ 0,5% Mn ≤ 1% S ≤ 0,01% P ≤ 0,02% le reste étant du fer et des impuretés résultant de l'élaboration.
La composition d'un alliage du type « durci par solution solide » comprend, en poids: 38% ≤ Ni + Co + Cu ≤ 42% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1% ≤ Nb ≤ 4% C ≤ 0,05% Si ≤ 0,5% Mn ≤ 0,5% S ≤ 0, 01 % P ≤ 0,02% le reste étant du fer et des impuretés résultant de l'élaboration.The composition of an alloy of the “hardened carbides” type comprises, by weight: 36% ≤ Ni + Co + Cu ≤ 40% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1.6% ≤ Mo ≤ 2.8% 0.4% ≤ Cr ≤ 1.5% 0.15% ≤ C ≤ 0.35% If ≤ 0.5% Mn ≤ 0.5% S ≤ 0.01% P ≤ 0.02% the remainder being iron and impurities resulting from processing.
The composition of an alloy of the “hardened beryllium” type comprises, by weight: 34% ≤ Ni + Co + Cu ≤ 38% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 0.15% ≤ Be ≤ 1% C ≤ 0.05% If ≤ 0.5% Mn ≤ 1% S ≤ 0.01% P ≤ 0.02% the remainder being iron and impurities resulting from processing.
The composition of an alloy of the “hardened by solid solution” type comprises, by weight: 38% ≤ Ni + Co + Cu ≤ 42% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1% ≤ Nb ≤ 4% C ≤ 0.05% If ≤ 0.5% Mn ≤ 0.5% S ≤ 0.01% P ≤ 0.02% the remainder being iron and impurities resulting from processing.

Cependant l'utilisation de l'alliage Fe-Ni du type « durci γ' » présente des avantages par rapport aux alliages du type « durci carbures », « durci béryllium » ou « durci par solution solide ».However, the use of the Fe-Ni alloy of the “hardened γ '” type presents advantages over alloys such as "hardened carbides", "hardened beryllium" or "Cured by solid solution".

En effet, l'alliage « durci γ' » est utilisé à l'état adouci pour former et souder le cadre, et le traitement thermique de durcissement est réalisé sur le cadre terminé. Il en résulte d'une part que les opérations de mise en forme sont faciles à réaliser et les soudures sont durcies par le traitement de durcissement.Indeed, the alloy "hardened γ '" is used in the softened state to form and weld the frame, and the hardening heat treatment is carried out on the finished frame. he on the one hand, the shaping operations are easy to perform and the welds are hardened by the hardening treatment.

En revanche, les autres alliages durcis doivent être utilisés à l'état durci (avant mise en forme et avant soudage). Il en résulte d'une part que les opérations de mise en forme sont plus difficiles à réaliser et d'autre part que les soudures sont adoucies par la chaleur de soudage.However, the other hardened alloys must be used in the hardened state (before shaping and before welding). It follows on the one hand that the operations of setting shaped are more difficult to achieve and on the other hand that the welds are softened by welding heat.

Claims (8)

Dispositif de masquage pour tube cathodique de visualisation en couleur à écran plat, du type comprenant un cadre support pour masque d'ombre tendu et un masque d'ombre tendu monté sur le cadre support de façon à être soumis à une tension à la température ambiante, caractérisé en ce que : le cadre support est en alliage Fe-Ni durci ayant un coefficient de dilatation thermique entre 20°C et 150°C inférieur à 5x10-6/K et une limite d'élasticité Rp0,2 à 20°C supérieure à 700 MPa, le masque d'ombre tendu est en alliage Fe-Ni ayant un coefficient de dilatation thermique entre 20°C et 150°C inférieur à 3x10-6/K,
l'alliage Fe-Ni durci dont est constitué le cadre support et l'alliage Fe-Ni dont est constitué le masque d'ombre étant choisis de telle sorte que : en dessous d'une température T1, le coefficient de dilatation moyen α20-T, entre 20°C et la température T, de l'alliage Fe-Ni durci dont est constitué le cadre support est supérieur au coefficient de dilatation moyen α20-T, entre 20°C et la température T, de l'alliage Fe-Ni dont est constitué le masque d'ombre, au dessus de ladite température T1, le coefficient de dilatation moyen α20-T, entre 20°C et la température T, de l'alliage Fe-Ni durci dont est constitué le cadre support est inférieur au coefficient de dilatation moyen α20-T, entre 20°C et la température T, de l'alliage Fe-Ni dont est constitué le masque d'ombre, ladite température T1 est inférieure à 350°C, et de préférence inférieure à 300°C. Masking device for flat-screen color display cathode ray tube, of the type comprising a support frame for a stretched shadow mask and a stretched shadow mask mounted on the support frame so as to be subjected to a tension at ambient temperature , characterized in that : the support frame is made of hardened Fe-Ni alloy having a coefficient of thermal expansion between 20 ° C and 150 ° C less than 5x10 -6 / K and an elastic limit Rp0.2 at 20 ° C greater than 700 MPa, the stretched shadow mask is made of Fe-Ni alloy having a coefficient of thermal expansion between 20 ° C and 150 ° C less than 3x10 -6 / K,
the hardened Fe-Ni alloy from which the support frame is made up and the Fe-Ni alloy from which the shadow mask is made up being chosen so that: below a temperature T 1 , the average coefficient of expansion α 20-T , between 20 ° C and the temperature T, of the hardened Fe-Ni alloy of which the support frame is made up is greater than the average coefficient of expansion α 20-T , between 20 ° C and the temperature T, of the Fe-Ni alloy of which the shadow mask is made, above said temperature T 1 , the average coefficient of expansion α 20-T , between 20 ° C and the temperature T, of the hardened Fe-Ni alloy of which the support frame is made is lower than the average coefficient of expansion α 20 -T , between 20 ° C and the temperature T, of the Fe-Ni alloy of which the shadow mask is made, said temperature T 1 is less than 350 ° C, and preferably less than 300 ° C. Dispositif selon la revendication 1 caractérisé en ce que l'alliage Fe-Ni durci dont est constitué le cadre support est un alliage FeNi du type « durci γ' » dont la composition chimique comprend, en poids : 40,5% ≤ Ni + Co + Cu ≤ 43,5% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1,5% ≤ Ti ≤ 3,5% 0,05% ≤ Al ≤ 1% C ≤ 0,05% Si ≤ 0,5% Mn ≤ 0,5% S ≤ 0,01% P ≤ 0,02% le reste étant du fer et des impuretés résultant de l'élaboration,
et l'alliage Fe-Ni dont est constitué le masque d'ombre est un alliage Fe-Ni dont la composition comprend, en poids : 32% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5,5% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr ≤ 2% 0 ≤ Mn ≤ 0,5% Si < 0,2% C < 0,02% S < 0,01% P < 0,02% Le reste étant du fer et des impuretés résultant de l'élaboration.Device according to Claim 1, characterized in that the hardened Fe-Ni alloy of which the support frame is made up is an FeNi alloy of the "hardened γ '" type, the chemical composition of which comprises, by weight: 40.5% ≤ Ni + Co + Cu ≤ 43.5% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1.5% ≤ Ti ≤ 3.5% 0.05% ≤ Al ≤ 1% C ≤ 0.05% If ≤ 0.5% Mn ≤ 0.5% S ≤ 0.01% P ≤ 0.02% the rest being iron and impurities resulting from the production,
and the Fe-Ni alloy of which the shadow mask is made is an Fe-Ni alloy, the composition of which comprises, by weight: 32% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5.5% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr ≤ 2% 0 ≤ Mn ≤ 0.5% If <0.2% C <0.02% S <0.01% P <0.02% The rest being iron and impurities resulting from processing. Dispositif selon la revendication 2 caractérisé en ce que la composition chimique de l'alliage Fe-Ni dont est constitué le masque d'ombre est telle que : 32% ≤ Ni + Co + Cu ≤ 35,5% 0% ≤ Co ≤ 4% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr < 0,2% Device according to Claim 2, characterized in that the chemical composition of the Fe-Ni alloy from which the shadow mask is made is such that: 32% ≤ Ni + Co + Cu ≤ 35.5% 0% ≤ Co ≤ 4% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr <0.2% Dispositif selon la revendication 2 caractérisé en ce que la composition chimique de l'alliage Fe-Ni dont est constitué le masque d'ombre est telle que : 33,5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5,5% 0% ≤ Cu ≤ 2% 0,2 % ≤ Nb + Ta + Mo + W + Zr ≤ 2% Device according to Claim 2, characterized in that the chemical composition of the Fe-Ni alloy from which the shadow mask is made is such that: 33.5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5.5% 0% ≤ Cu ≤ 2% 0.2% ≤ Nb + Ta + Mo + W + Zr ≤ 2% Dispositif selon la revendication 1 caractérisé en ce que l'alliage Fe-Ni durci dont est constitué le cadre support est un alliage FeNi du type « durci γ' » dont la composition chimique comprend, en poids : 43,5% ≤ Ni + Co + Cu ≤ 45,5% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1,5% ≤ Ti ≤ 3,5% 0,05% ≤ Al ≤ 1% C ≤ 0,05% Si ≤ 0,5% Mn ≤ 0,5% S ≤ 0,01% P ≤ 0,02% le reste étant du fer et des impuretés résultant de l'élaboration,
et l'alliage Fe-Ni dont est constitué le masque d'ombre est un alliage Fe-Ni dont la composition comprend, en poids : 35,5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5,5% 0% ≤ Cu ≤ 2% 0 ≤ Mn ≤ 0,5% Si < 0,2% C < 0,02% S < 0,01% P < 0,02% Le reste étant du fer et des impuretés résultant de l'élaboration.Device according to Claim 1, characterized in that the hardened Fe-Ni alloy of which the support frame is made up is an FeNi alloy of the "hardened γ '" type, the chemical composition of which comprises, by weight: 43.5% ≤ Ni + Co + Cu ≤ 45.5% 0% ≤ Co ≤ 5% 0% ≤ Cu ≤ 3% 1.5% ≤ Ti ≤ 3.5% 0.05% ≤ Al ≤ 1% C ≤ 0.05% If ≤ 0.5% Mn ≤ 0.5% S ≤ 0.01% P ≤ 0.02% the rest being iron and impurities resulting from the production,
and the Fe-Ni alloy of which the shadow mask is made is an Fe-Ni alloy, the composition of which comprises, by weight: 35.5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5.5% 0% ≤ Cu ≤ 2% 0 ≤ Mn ≤ 0.5% If <0.2% C <0.02% S <0.01% P <0.02% The rest being iron and impurities resulting from processing. Masque d'ombre tendu caractérisé en ce que la composition chimique de l'alliage Fe-Ni est telle que: 32% ≤ Ni + Co + Cu ≤ 35,5% 0% ≤ Co ≤ 4% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr < 0,2% Stretch shadow mask characterized in that the chemical composition of the Fe-Ni alloy is such that: 32% ≤ Ni + Co + Cu ≤ 35.5% 0% ≤ Co ≤ 4% 0% ≤ Cu ≤ 2% 0% ≤ Nb + Ta + Mo + W + Zr <0.2% Masque d'ombre tendu caractérisé en ce que la composition chimique de l'alliage Fe-Ni est telle que: 33,5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5,5% 0% ≤ Cu ≤ 2% 0,2% ≤ Nb + Ta + Mo + W + Zr ≤ 2% Stretch shadow mask characterized in that the chemical composition of the Fe-Ni alloy is such that: 33.5% ≤ Ni + Co + Cu ≤ 37% 0% ≤ Co ≤ 5.5% 0% ≤ Cu ≤ 2% 0.2% ≤ Nb + Ta + Mo + W + Zr ≤ 2% Dispositif selon la revendication 1 caractérisé en ce que l'alliage Fe-Ni durci dont est constitué le cadre est un alliage Fe-Ni durci du type « durci berrylium », du type « durci carbures » ou du type « durci par solution solide ».Device according to Claim 1, characterized in that the hardened Fe-Ni alloy of which the frame is made is a hardened Fe-Ni alloy of the "hardened berrylium" type, of the "hardened carbides" type or of the "hardened by solid solution" type. .
EP01400812A 2000-03-31 2001-03-29 Masking device for a colour flat screen cathode ray tube comprising a tension-type iron-nickel-alloy shadow mask Withdrawn EP1138797A1 (en)

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FR0004080 2000-03-31
FR0004080A FR2807269B1 (en) 2000-03-31 2000-03-31 MASKING DEVICE FOR FLAT SCREEN COLOR DISPLAY CATHODIC TUBE WITH SHADOW MASK TENSIONED IN FE-NI ALLOYS

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006005250B4 (en) * 2006-02-02 2010-04-29 Thyssenkrupp Vdm Gmbh Iron-nickel alloy

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6266654B1 (en) * 1992-12-15 2001-07-24 Softlock.Com, Inc. Method for tracking software lineage
CN116024524A (en) * 2017-11-21 2023-04-28 Lg伊诺特有限公司 Metal plate and deposition mask using the same
CN109746455B (en) * 2019-03-19 2022-08-12 湖南恒基粉末科技有限责任公司 Copper-containing kovar alloy and preparation method thereof
CN114107838A (en) * 2020-09-01 2022-03-01 宝武特种冶金有限公司 High-strength invar alloy wire and manufacturing method thereof

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4713576A (en) * 1985-04-24 1987-12-15 Hitachi, Ltd. Color picture tube with shadow mask
US5502350A (en) * 1993-07-05 1996-03-26 Hitachi Metals Ltd. Shadow mask support member having high strength and thermal deformation resistant low-expansion alloy plate and high expansion alloy plate and method of producing the same
JPH09324243A (en) * 1996-06-04 1997-12-16 Toshiba Corp Low thermal expansion alloy having coefficient of thermal expansion approximate to that of si
US5811918A (en) * 1994-01-17 1998-09-22 U.S. Philips Corporation Shadow mask of the nickel-iron type having specific composition
DE19919812A1 (en) * 1998-04-30 1999-11-04 Dainippon Printing Co Ltd Shadow mask for color picture tube, e.g. for color television and computer color displays
EP1063304A1 (en) * 1999-06-22 2000-12-27 Imphy Ugine Precision Masking device for a colour flat screen cathode ray tube comprising a supporting frame for planar mask and planar mask

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4639576A (en) * 1985-03-22 1987-01-27 Inco Alloys International, Inc. Welding electrode
FR2728724B1 (en) * 1994-12-27 1997-01-24 Imphy Sa METHOD FOR MANUFACTURING AN IRON-NICKEL ALLOY SHADOW MASK
US5914557A (en) * 1997-05-20 1999-06-22 Kabushiki Kaisha Toshiba Color cathode ray tube
KR100259299B1 (en) * 1998-04-21 2000-06-15 Lg Electronics Inc Shadow mask of color cathode ray tube and method for fabricating the same

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4713576A (en) * 1985-04-24 1987-12-15 Hitachi, Ltd. Color picture tube with shadow mask
US5502350A (en) * 1993-07-05 1996-03-26 Hitachi Metals Ltd. Shadow mask support member having high strength and thermal deformation resistant low-expansion alloy plate and high expansion alloy plate and method of producing the same
US5811918A (en) * 1994-01-17 1998-09-22 U.S. Philips Corporation Shadow mask of the nickel-iron type having specific composition
JPH09324243A (en) * 1996-06-04 1997-12-16 Toshiba Corp Low thermal expansion alloy having coefficient of thermal expansion approximate to that of si
DE19919812A1 (en) * 1998-04-30 1999-11-04 Dainippon Printing Co Ltd Shadow mask for color picture tube, e.g. for color television and computer color displays
EP1063304A1 (en) * 1999-06-22 2000-12-27 Imphy Ugine Precision Masking device for a colour flat screen cathode ray tube comprising a supporting frame for planar mask and planar mask

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 1998, no. 04 31 March 1998 (1998-03-31) *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006005250B4 (en) * 2006-02-02 2010-04-29 Thyssenkrupp Vdm Gmbh Iron-nickel alloy
US8808475B2 (en) 2006-02-02 2014-08-19 Outokumpu Vdm Gmbh Iron-nickel alloy

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BR0101265A (en) 2001-11-06
MXPA01003235A (en) 2004-07-30
PL346817A1 (en) 2001-10-08
JP2001297710A (en) 2001-10-26
KR20010095131A (en) 2001-11-03
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RU2001108595A (en) 2003-03-10
TW492034B (en) 2002-06-21

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