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US 4,070,583 AGranted
Rare earth oxyhalide phosphors coactivated with terbium, thulium
AssigneeGeneral Electric Company
InventorJacob G. Rabatin
Life of this patent
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Abstract
Oxyhalides of lanthanum and/or gadolinium coactivated with thulium and terbium are phosphors found to have the advantages of reduced afterglow and increased ultraviolet emisson. The relative speed of the phosphors is also quite high. These phosphors are used in x-ray image converters generally, and can be used in such devices as x-ray image intensifier tubes, in fluoroscopic screens and in radiographic intensifier screens.
Claims12
A rare earth oxyhalide phosphor according to the formula Ln.sub.1-y-w OX:Tb.sub.y Tm.sub.w
- wherein Ln is one or more of lanthanum and gadolinium;
- x is one or more of chlorine and bromine;
- Tb and Tm are present as coactivators;
- y is from about 0.0005 to 0.010 moles per mole of the selected oxyhalide;
- and
- w is from about 0.00005 to 0.005 moles per mole of the selected oxyhalide;
- the phosphor exhibiting relatively low afterglow and relatively high ultraviolet light emission.
4 more elements
An image converter comprising:
- a polyester base passing visible light therethrough and having a silver halide emulsion layer coating a first surface of the base;
- a coactivated phosphor layer positioned in spaced registry from the emulsion layer, the phosphor being a rare earth oxyhalide according to the formula Ln.sub.1-y-OX:Tb.sub.y Tm.sub.w
- wherein
- Ln is one or more of lanthanum and gadolinium;
- x is one or more of chlorine and bromine;
- Tb and Tm are present as coactivators;
- y is from about 0.0005 to 0.010 moles per mole of the selected oxyhalide;
- and
- w is from about 0.00005 to 0.005 moles per mole of the selected oxyhalide;
- the phosphor exhibiting relatively low afterglow and relatively high ultraviolet light emission;
- a transparent layer abutted at opposite surfaces thereof by the emulsion layer and a first surface of the phosphor layer;
- a flexible backing positioned in spaced registry from the phosphor layer;
- and
- a reflector layer positioned in abutting relation, at opposite surfaces thereof by the flexible backing and the phosphor layer.
11 more elements
Dependencies are inferred from the claim text.