EP0317392A1 - Hochleuchtender Farbschirm für Kathodenstrahlröhre und Verfahren zur Herstellung desselben - Google Patents

Hochleuchtender Farbschirm für Kathodenstrahlröhre und Verfahren zur Herstellung desselben Download PDF

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Publication number
EP0317392A1
EP0317392A1 EP88402806A EP88402806A EP0317392A1 EP 0317392 A1 EP0317392 A1 EP 0317392A1 EP 88402806 A EP88402806 A EP 88402806A EP 88402806 A EP88402806 A EP 88402806A EP 0317392 A1 EP0317392 A1 EP 0317392A1
Authority
EP
European Patent Office
Prior art keywords
layer
screen
barrier
silicon dioxide
phosphor
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.)
Granted
Application number
EP88402806A
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English (en)
French (fr)
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EP0317392B1 (de
Inventor
Jean-Pierre Galves
Pierre Merloz
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.)
Thales SA
Original Assignee
Thomson CSF SA
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Filing date
Publication date
Application filed by Thomson CSF SA filed Critical Thomson CSF SA
Publication of EP0317392A1 publication Critical patent/EP0317392A1/de
Application granted granted Critical
Publication of EP0317392B1 publication Critical patent/EP0317392B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/18—Luminescent screens
    • H01J29/26—Luminescent screens with superimposed luminescent layers
    • 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
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/18—Luminescent screens
    • H01J29/28—Luminescent screens with protective, conductive or reflective layers

Definitions

  • the invention relates to a screen for cathode ray tubes with traces of high luminance and of color adjustable by the acceleration voltage of the beam, it relates particularly to the structure of this screen. It also relates to its manufacturing process.
  • cathodoluminescent screens include two phosphors of different fluorescence, green and red in the following. They are represented schematically in the form of two homogeneous layers, each consisting of one of the phosphors, separated or not by a layer of an inert or non-luminescent material, emitting no light under the effect of a bombardment of electrons.
  • the acceleration voltage V of the beam that is to say according to the energy of the electrons of the beam, only the first of these layers, which will be assumed to be the red fluorescence layer in what follows, undergoes the excitation of the beam, or, if this tension is sufficient, this layer and all or part of the second, made of a phosphor with green fluorescence undergo the excitation of the beam.
  • Green fluorescence begins to be excited only from a certain value of this voltage, that sufficient for the energy of the electrons to allow them to enter the screen - hence the expression of screens with penetration previous - up to the green phosphor layer, after crossing the red phosphor layer and, possibly, the inert layer; this value of the voltage will be designated in the following by V0, the green fluorescence predominates and the trace takes on the green color. Between the two values V0 and V1 we obtain, depending on the value of V, intermediate colors between green and red according to the proportions in the trace of the two excited fluorescences.
  • Another of these structures comprises a mixture of crystals of the two red and green phosphors, the crystals of the latter having been coated before the operation of mixing a film of inert material. Generally, with such mixtures, a luminance substantially greater than that of the preceding structure is obtained.
  • the red phosphor is integrated into the structure in the form of small grains surrounding the inert layer covering larger grains of the green phosphor.
  • the screen consists of superimposed layers and, as detailed below, it includes the following elements: - A transparent support 1, made of glass, constituting the screen proper; - A layer 2 of a green phosphor consisting of crystals 20, this layer being deposited according to a well-known sedimentation technique; - A barrier layer 3 comprising a transparent inert material.
  • This layer is conventionally made up either of zinc sulfide (ZnS) or of silicon oxide (SiO2).
  • a layer 4 of a red phosphor made up of crystals 40 this layer being deposited either by centrifugation, the support 1 rotating around an axis parallel to its plane, or by fixing the screen on a spinner whose axis is confused with that of the screen.
  • the thickness deposited depends on the operating voltages of the tube.
  • the crystals are either yttrium vanadate, or a yttrium oxysulfide or a gadolinium oxide, doped with europium; - and finally a thin conductive layer generally made of aluminum. This layer is brought to the high voltage of the tube and makes it possible to eliminate the electrostatic charges. It also serves as a reflector in order to obtain unidirectional radiation.
  • the barrier layer 3 is deposited after the deposition of the first phosphor 2 in the following manner: - An organic film is produced by known means, on the green phosphor layer, this film serving as a temporary support for the inert material constituting the barrier layer 3. A polymer, butyl methacrylate, is generally used, and its formation is carried out by a wet deposit on the screen of a solution containing this product. After the water has evaporated, the film is bonded to the layer of green phosphor. Another solution consists in using a nitrocellulose film produced in a conventional manner according to the known art; - Then the inert material is deposited by vacuum evaporation either by the Joule effect or with the electron gun. The measurement and adjustment of the deposited thickness is made by known means in order to achieve the desired thickness which makes it possible to obtain the desired threshold voltage constituting a barrier for the electrons which have too low an energy.
  • the temporary organic film is removed during the subsequent heat treatments applied to the cathode ray tube.
  • this temporary support film is essential so that the inert layer has a flat surface and a thickness as constant as possible throughout its extent in order to obtain a good functioning of the screens.
  • the inert material when it is silicon oxide undergoes stresses in extension which cause cracks and which also cause a tearing of the organic film.
  • the high zinc sulphide index n 2.3, limits the optical transmission in particular of the red radiation coming from the red luminophore.
  • the present invention overcomes all these drawbacks. Its subject is a high luminance color screen for cathode ray tubes, in which the barrier layer has all of the following characteristics: good transparency optical, uniform thickness suitable for stopping electrons, good mechanical strength, chemical stability under vacuum, under electronic bombardment and in the presence of various products such as water or organic solvents.
  • the invention therefore relates to a high luminance color screen for cathode-ray tube comprising two fluorescence phosphors of different colors, the visible trace of which under the effect of electron bombardment has a color adjustable by the acceleration voltage of the beam of said beams.
  • electrons, variable, in operation, between two extreme values V0 and V1 in which the two phosphors are arranged on the transparent support of said screen in superimposed layers made of crystal powders of each of said phosphors, separated from each other by a barrier with faces planar, characterized in that the barrier with planar faces comprises a first layer of silicon dioxide, a layer of zinc sulfide and a second layer of silicon dioxide, the layer of zinc sulfide being between the two layers of diozyde silicon.
  • Another object of the invention consists in producing a barrier in which the layers of silicon dioxide have a thickness substantially equal to 0.1 ⁇ m in order to minimize the overall refractive index of the barrier, to increase the optical transmission, to protect the zinc sulfide and to maintain the internal stresses of this barrier in compression.
  • Another object of the invention consists in producing a screen in which the powder constituting the deepest phosphor layer of the screen, called the first layer, that is to say that in contact with the support, is made phosphor P1 of the JEDEC specification and has a particle size of 6 micrometers or less, and in that the powder constituting the other phosphor layer, called the second layer, is made of yttrium vanadate doped with europium and has a particle size of 0.6 micrometer, and in that these layers have thicknesses corresponding substantially to respective weights of 1 to 3 mg and 0.15 milligrams per square centimeter.
  • the invention also relates to a screen in which the minimum operating voltage is from 7 to 10 kV and the maximum voltage from 12 to 17 kV.
  • the invention also relates to a screen in which the traces have the color green (550 nm) at maximum voltage and the color red (610 nm) at minimum voltage.
  • the invention also consists of a method for producing a high-luminance color screen for cathode-ray tube, characterized in that it consists in successively carrying out the following steps: - deposit of the first phosphor layer on the transparent screen; - depositing an organic film on this first phosphor layer; - deposition of the first layer of silicon oxide; - deposition of the zinc sulfide layer on the silicon oxide layer; - Deposition of the second layer of silicon oxide on the zinc sulfide layer, these last three layers forming an inert material constituting a barrier to electrons which have an acceleration voltage below the voltage threshold which this barrier constitutes; - deposition of the second phosphor layer on the second layer of silicon dioxide; - depositing an electrically conductive layer; - removal of the organic layer by heat treatment of the structure.
  • FIGS. 1 and 2 show a fragment of a penetrating screen and more particularly the constituent structure of these screens.
  • a thick glass support 1 a layer made of a green phosphor powder, a barrier 3 made of inert material 3, a layer made of a red phosphor powder 4, and a thin conductive layer 5.
  • the screen shown in this figure 2 is produced, as will be explained below: on the thick glass support 1, layer 2 is deposited, of green phosphor powder of type P1 of the JEDEC specification, publication of "Electronic Industry Association", Engineering Department, according to one of the known techniques, sedimentation for example .
  • the powder in question has a particle size of approximately 6 micrometers; the amount deposited is 3 milligrams per square centimeter.
  • the various layers constituting the barrier 3 are deposited.
  • a temporary support consisting of an organic film 35 is deposited.
  • This support 35 makes it possible to obtain a flat surface for the barrier, without this temporary support, there would be during the constitution of the barrier. , infiltrations through the crystals 20 of the green phosphor.
  • organic film 35 a polymer is used, butyl methacrylate in solution which sticks to the phosphor layer 2 after evaporation of the water.
  • This temporary organic film 35 is removed during the subsequent heat treatments applied to the cathode ray tube.
  • a first layer 31 made of an inert material this material being silicon dioxide (SiO2).
  • This material being silicon dioxide (SiO2).
  • the deposition is carried out by a conventional technique of vacuum evaporation of the silicon dioxide using a electrons. This technique also makes it possible to control the uniformity of the deposit and to obtain the desired thickness.
  • a layer 32 is then deposited consisting of an inert material of a different nature, this material being zinc sulfide.
  • the deposition is also carried out by vacuum evaporation of the zinc sulfide by the Joule effect using a molybdenum crucible containing the zinc sulfide.
  • the thickness is also automatically controlled by conventional means. It is this thickness which fixes the barrier threshold for the electrons. By controlling this thickness, the desired threshold V0 is obtained.
  • the electrons which have an acceleration voltage lower than the voltage V0 are stopped and the electrons which have a voltage higher than V0 cross the barrier.
  • a second layer of silicon dioxide 33 is then deposited on this layer of zinc sulfide 32. This deposition is carried out in the same way as the first layer 31, that is to say by vacuum evaporation of the silicon dioxide to using an electron gun.
  • the layer of the second phosphor is deposited. It is a red phosphor powder having a particle size substantially finer than that of layer 2, ie approximately 0.6 ⁇ m. This powder consists either of yttrium vanadate, or a yttrium oxysulfide, or a gadolinium oxide, doped with europium.
  • the deposition takes place by centrifugation, the support 1 rotating around an axis parallel to its plane, or by fixing the support screen on a spindle whose axis coincides with that of the screen.
  • the thickness deposited depends on the operating voltages of the tube. For a voltage V0 of 10 kV and a barrier of inert material 3 with a thickness of 1.2 ⁇ m, the layer of red phosphor 4 is 0.15 mg / cm2.
  • the conductive layer is then deposited forming an aluminum film which is brought into operation at the high voltage of the tube.
  • the screen thus formed operates with a high voltage V1 of 17 kV.
  • These voltages of 10kV and 17kV correspond to colors of the red and green traces of 610 nanometers and 550 nanometers respectively.
  • the structure of the penetration screen according to the invention is therefore in the form of superposed polycrystalline layers between which a barrier is placed.
  • This barrier consists of inert material in the form of three layers, a layer of zinc sulphide and two layers of silicon dioxide, the layer of zinc sulphide being taken between the layers of silicon dioxide.
  • the thicknesses of the silicon dioxide layers are practically independent of the operating voltages V0 and V1, and are chosen in order to improve the optical transmission of the layer of zinc sulfide which has a high refractive index. By choosing a thickness of 1000 ⁇ ⁇ 50, the overall index of refraction of the barrier is reduced and the optical transmission is therefore improved.

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  • Luminescent Compositions (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
EP88402806A 1987-11-13 1988-11-08 Hochleuchtender Farbschirm für Kathodenstrahlröhre und Verfahren zur Herstellung desselben Expired - Lifetime EP0317392B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8715674 1987-11-13
FR8715674A FR2623329B1 (fr) 1987-11-13 1987-11-13 Ecran de couleur a haute luminance pour tube a rayons cathodiques et procede de realisation d'un tel ecran

Publications (2)

Publication Number Publication Date
EP0317392A1 true EP0317392A1 (de) 1989-05-24
EP0317392B1 EP0317392B1 (de) 1991-08-07

Family

ID=9356740

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88402806A Expired - Lifetime EP0317392B1 (de) 1987-11-13 1988-11-08 Hochleuchtender Farbschirm für Kathodenstrahlröhre und Verfahren zur Herstellung desselben

Country Status (5)

Country Link
US (1) US4906892A (de)
EP (1) EP0317392B1 (de)
JP (1) JPH01161642A (de)
DE (1) DE3864123D1 (de)
FR (1) FR2623329B1 (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111243922B (zh) * 2020-01-16 2022-11-18 中国建筑材料科学研究总院有限公司 荧光薄膜屏、其制备方法及其在微通道板像增强器的应用

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2356266A1 (fr) * 1976-06-25 1978-01-20 Thomson Csf Ecran de couleur a haute luminance pour tubes a rayons cathodiques, son procede de fabrication et tube cathodique incorporant un tel ecran

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE506607A (de) * 1950-10-24
US3231775A (en) * 1961-12-27 1966-01-25 Rca Corp Cascaded phosphor layers for color display including one of discrete coherent particles
US3517243A (en) * 1969-03-17 1970-06-23 Texas Instruments Inc Color display screen employing two layers of phosphors,particles in the inner layer being small with respect to those in the outer layer and discontinuous in coverage
US3603830A (en) * 1969-08-26 1971-09-07 Sylvania Electric Prod Penetration-type color tube with phosphors separated by conductive barrier layer

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2356266A1 (fr) * 1976-06-25 1978-01-20 Thomson Csf Ecran de couleur a haute luminance pour tubes a rayons cathodiques, son procede de fabrication et tube cathodique incorporant un tel ecran

Also Published As

Publication number Publication date
JPH01161642A (ja) 1989-06-26
DE3864123D1 (de) 1991-09-12
FR2623329A1 (fr) 1989-05-19
US4906892A (en) 1990-03-06
FR2623329B1 (fr) 1990-02-16
EP0317392B1 (de) 1991-08-07

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