Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
  • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
  • C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
  • C09K11/7783—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals one of which being europium
  • C09K11/7784—Chalcogenides
  • C09K11/7787—Oxides
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
  • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
  • C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
  • C09K11/7766—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals
  • C09K11/7774—Aluminates
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
  • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
  • C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
  • C09K11/7766—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals
  • C09K11/7767—Chalcogenides
  • C09K11/7769—Oxides

Definitions

• the invention is concerned with luminescent color display devices *
• Display devices such as, e.g., cathode ray tubes typically include a luminescent screen which locally emits optical radiation in response to locally incident electron or electromagnetic radiation.
• Luminescent screen materials may be chosen with respect to a number of criteria; in many applications such as, e.g., high resolution displays, projection systems, and direct viewing systems under strong ambient lighting conditions there is a particular concern with brightness of emitted radiation. Accordingly, luminescent screen materials are desired which are highly efficient in emitting radiation of a desired wavelength.
• Display devices may include luminescent materials or phosphors in powder form; however, such materials tend to have shortcomings such as, e.g., poor thermal properties, degradation of efficiency with stimulating radiation dose, and limited resolution.
• single-crystal slabs or layers of luminescent materials have been found to be capable of withstanding input power densities in excess of 10 10W/m2 without measurable degradation and to have improved resolution as compared to powder phosphor targets.
• Visual display devices embodying the invention comprise a source of stimulating electron or electromagnetic radiation, typically including deflection and modulation means, and a member comprising a substantially single-crystal phosphor material which is a garnet material consisting essentially of a composition substantially as represented by the formula
• R represents at least one rare earth element
• x_ is in the preferred range from 0.005 to 0.5, where preferably is less than or equal to 2.995, and where _z preferably is less than or equal to 5.
• rare earth elements Nd, Eu, Tm, and Tb are limited to amounts corresponding to y- values which are less than 0.01 and preferably less than or equal to 0.005.
• Preferred yttrium aluminum garnets have z_ less than or equal to 0.4 and preferably ⁇ _ less than or equal to 0 ⁇ 05,. and rare, earth elemeata other than Lu and Gd are preferably limited such that their combined contribution to the combined amount of rare earth elements is represented by a value of which is less than or equal to 0.2.
• suitable bismuth-containing garnet materials emit electromagnetic radiation whose spectrum has a peak at a wavelength which is greater than or equal to 425 nanometers.
• FIG. 1 is a schematic cross-sectional view of a cathode ray display device in accordance with the invention.
• FIG. 2 is a graphic representation of spectra of light output of two luminescent materials.
• FIG. 1 shows a cathode ray display device comprising electron radiation source 11 with electrical connection pins 12, enclosure 13, garnet substrate 14, and bismuth-activated luminescent film 15 in accordance with the invention.
• FIG. 2 shows light output intensity curve 21 representing luminescence intensity of a prior-art polycrystalline bismuth-activated garnet material, and curve 22 representing luminescence intensity of a bismuth- activated garnet material in accordance with the invention.
• Curve 22 shows an intensity peak corresponding to a wavelength near 450 nanometers.
• Display devices embodying the invention comprise a member such as, e.g., a screen comprising a substantially single-crystal material having a composition as described above.
• substantially single-crystal structure may include faults such as, e.g., dislocations.
• a member may comprise other phosphor materials which luminesce at different wavelengths as, e.g., in color display devices; however, monochromatic devices are not precluded.
• a luminescent material typically is .in the form of a layer as epitaxially deposited on a crystallographically compatible substrate.
• Yttrium- aluminum garnet substrates are customary, typically having a [111] crystalline orientation.
• compositions such as, e.g., those which comprise little or no yttrium and for which y_ is in a preferred range of from 2.5 to 2.995.
• such materials preferably comprise a significant amount of gallium as, e.g., in a composition such as
• a resulting layer may be conveniently matched to a gadolinium-gallium garnet substrate.
• ⁇ Deposition of the film on the substrate is conveniently effected by liquid phase epitaxy, i.e., by bringing a surface of a substrate in contact with a fluxed melt of garnet constituent oxides while melt temperature is regulated to result in supersaturation of garnet constituents in the vicinity of the liquid-solid interface.
• Example. A melt was prepared by heating a mixture of approximately 18.40 grams Y2O3, approximately 33.58 grams AI2O3, approximately 1100.0 grams Bi2 ⁇ 3, and approximately 41.07 grams B2O3.
• An yttrium-aluminum garnet substrate was brought in contact with the melt surface while the melt was at a temperature of 1025 degrees C, and a film having a thickness of approximately 5.86 micrometers was thus grown at a rate of approximately 1.43 micrometers per minute.
• the grown film had a composition as approximately represented by the formula * 2 .95 Bi 0.05 Al 5°12*

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• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Luminescent Compositions (AREA)

Applications Claiming Priority (2)

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• 1985
  • 1985-05-09 JP JP60502283A patent/JPS61502685A/ja active Pending
  • 1985-05-09 WO PCT/US1985/000851 patent/WO1986000633A1/en not_active Application Discontinuation
  • 1985-05-09 EP EP85902773A patent/EP0190153A1/en not_active Withdrawn

Non-Patent Citations (1)

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