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AssigneeU.S. Philips Corporation
InventorsJudicus M. P. J. Verstegen, Johannus G. Verlijsdonk, Emiel P. J. de Meester, Willebrordus H. M. M. van de Spijker, Johannes G. Verriet
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A luminescent screen provided with a luminescent material having the hexagonal crystal structure, which material is an aluminate, a gallate or an aluminate gallate. The crystal structure of the luminescent material corresponds to that of at least one of the compounds .beta.-aluminium, .beta."-alumina and the hexagonal ferrites. The luminescent material is activated by at least one of the elements manganese, europium, lead, thallium, cerium, indium, terbium, dysprosium and bismuth and is a ternary compound whose composition can be represented in the ternary phase diagram ABC in which A represents at least one of the oxides 1/4Na.sub.2 O, 1/2K.sub.2 O, 1/2Rb.sub.2 O, 1/2Cs.sub.2 O, CaO, SrO, BaO, 1/2La.sub.2 O.sub.3, 1/2Ce.sub.2 O.sub.3, 1/2Tb.sub.2 O.sub.3, 1/2Dy.sub.2 O.sub.3, 1/2Bi.sub.2 O.sub.3, EuO, PbO, 1/2Tl.sub.2 O and 1/2In.sub.2 O, in which B represents at least one of the oxides Al.sub.2 O.sub.3 and Ga.sub.2 O.sub.3 in which up to 25 mol. % of the oxides denoted by B may be replaced by Sc.sub.2 O.sub. 3 and in which C represents at least one of the oxides MgO, ZnO, BeO, 1/2LiAlO.sub.2 and 1/2LiGaO.sub.2. The content of A is more than zero and less than that of B and the content of C is more than zero and less than 0.6.
A luminescent material having a hexagonal crystal structure corresponding to .beta.-alumina, .beta."--alumina or the hexagonal ferrites, said luminescent material being activated by bivalent europium in the amount of from about 0.5 at.% to about 25 at.% of the metal of the oxide A in the ternary phase diagram ABC in FIG. 1, said luminescent material being a ternary compound having a composition coming within the sides of the quadrangle RBPQ in said ternary phase diagram ABC wherein A is at least one oxide selected from the group consisting of SrO and BaO, B is selected from the group consisting of Al.sub.2 O.sub.3 and a mixture of Al.sub.2 O.sub.3 and Ga.sub.2 O.sub.3 with at least 75 mol % of B being Al.sub.2 O.sub.3 and C is at least one oxide selected from the group consisting of ZnO and MgO, the content of A being about 0.04 to about 0.35, the content of B being about 0.43 to about 0.85 and the content of C being about 0.075 to about 0.36.
A luminescent material having a hexagonal crystal structure corresponding to .beta.--alumina, "--alumina or the hexagonal ferrites, said luminescent material being activated by bivalent manganese in the amount of from about 0.35 at.% to about 8.3 at.% of the metal of the oxide C of the ternary phase diagram ABC in FIG. 1, said luminescent material being a ternary compound having a composition coming within the sides of the quadrangle RBPQ in said ternary phase diagram ABC wherein A is at least one oxide selected from the group consisting of SrO and BaO, B is at least one oxide selected from the group consisting of Al.sub.2 O.sub.3 and Ga.sub.2 O.sub.3 and C is MgO, the content of A being about 0.09 to about 0.20, the content of B being about 0.60 to 0.82 and the content of C being about 0.05 to about 0.20.
A luminescent material having a hexagonal crystal structure corresponding to .beta.--alumina, .beta."-alumina or the hexagonal ferrites, said luminescent material being activated by a mixture of bivalent europium in the amount of from about 3.1 at.% to about 75 at.% of the metal of the oxide A and bivalent manganese in the amount of from about 4 at.% to about 50 at.% of the metal of the oxide C of the ternary phase diagram ABC in FIG. 1, said luminescent material being a ternary compound a composition coming within the sides of the quadrangle RBPQ in said ternary phase diagram ABC wherein A is at least one oxide selected from the group consisting of SrO and BaO, B is selected from the group consisting of Al.sub.2 O.sub.3 and mixtures of Al.sub.2 O.sub.3 and Ga.sub.2 O.sub.3 with at least 75 mol % of B being Al.sub.2 O.sub.3 and C is MgO, the content of A being about 0.04 to about 0.20, the content of B being about 0.60 to about 0.82 and the content of C being about 0.05 to about 0.35.
A luminescent material of the formula Ba.sub.1.6 Eu.sub.0.4 Zn.sub.4.2 Mn.sub.0.8 Al.sub.32 O.sub.55 wherein Eu and Mn are both in the bivalent state.
A luminescent material of the formula Ba.sub.2 Zn.sub.1.993 Mn.sub.0.007 Ga.sub.12 O.sub.22 wherein Mn is in the bivalent state.
Dependencies are inferred from the claim text.