Penetration phosphors for display devices
AssigneeSperry Rand Corporation
InventorStanley F. Ignasiak
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Abstract
La.sub.2 O.sub.2 S particles are employed as a carrier host in conjunction with terbium activator ions in a cathodo-luminescent penetration phosphor composition for cathode ray display tubes. A thin layer of La.sub.2 O.sub.2 SO.sub.4 :Tb or La.sub.2 O.sub.2 SO.sub.4 :Tb,Eu is utilized to provide a barrier which must be penetrated by excitation electrons to produce green spectral emission from the particle thereby increasing the voltage-turn-on characteristic of the phosphor. Additionally, methods are disclosed for synthesizing the same in addition to an improved method for synthesizing a penetration phosphor particle comprising a core of La.sub.2 O.sub.2 S:Tb and a barrier layer of La.sub.2 O.sub.2 S:Tb,Eu.
Claims14
A method for making a cathodo-luminescent particle having a central region consisting of La.sub.2 O.sub.2 S with Tb.sub.2 O.sub.2 S uniformly distributed therethrough and a peripheral region of La.sub.2 O.sub.2 SO.sub.4 with a distribution of Tb.sub.2 O.sub.2 SO.sub.4 therethrough comprising:
- selecting a host material consisting of La.sub.2 O.sub.2 S particles with a uniform distribution of Tb.sub.2 O.sub.2 S therethrough,
- annealing said host material with oxygen for at least 25 minutes at a temperature in excess of 700.degree. C, and
- air cooling said material.
A method for producing a cathodo-luminescent particle having a central region consisting of La.sub.2 O.sub.2 S with Tb.sub.2 O.sub.2 S uniformly distributed therethrough and a peripheral region of La.sub.2 O.sub.2 SO.sub.4 with a distribution of Tb.sub.2 O.sub.2 SO.sub.4 and Eu.sub.2 O.sub.2 SO.sub.4 therethrough comprising:
- selecting a host material of La.sub.2 O.sub.2 S particles with a uniform distribution of Tb.sub.2 O.sub.2 S therethrough,
- combining said host material with an organic Eu compound,
- annealing the mixture of the organic Eu compound and the host material with oxygen for at least 25 minutes at a temperature in excess of 700.degree. C, and
- air cooling said mixture.
The method of producing a penetration phosphor particle for use in an electron tube and having a central region of La.sub.2 O.sub.2 S with a substantially smaller concentration of Tb.sub.2 O.sub.2 S uniformly distributed therethrough and a pheripheral region surrounding said central region comprised on La.sub.2 O.sub.2 S with substantially smaller concentrations of Tb.sub.2 O.sub.2 S and Eu.sub.2 O.sub.2 S distributed therethrough comprising:
- selecting a host material of La.sub.2 O.sub.2 S particles having a uniform distribution of Tb.sub.2 O.sub.2 S therethrough,
- combining said host material with an organic Eu compound,
- annealing of the mixture of the host material and the organic Eu compound with oxygen for a period in excess of 20 minutes and at a temperature in excess of 700.degree. C,
- firing the product from the preceding step in a furnace in an atmosphere comprising H.sub.2 S and an inert gas bubbled through H.sub.2 O, and
- cooling the product in an atmosphere of an inert gas.
Dependencies are inferred from the claim text.