U.S. Philips Corporation

Judicus M Verstegen

Willebrordus H Van De Spijker

Johannus G Verlijsdonk

Johannes G Verriet

Emiel P De Meester

Lambertus Wilhelmus Manders

Dragutin Radielovic

Cornelis Wilhelmus Schetters

Emiel Petrus De Meester

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

Cerium and terbium activated luminescent material and mercury vapor

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 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.

Luminescent material and discharge lamp containing the same

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.

Luminescent material and discharge lamp and cathode ray tube containing

A luminescent beryllium-containing silicate activated by bivalent europium defined by the formula Me.sub.1-x Eu.sub.x Be.sub.a Si.sub.a O.sub.3a+1, in which 0.005 .ltoreq.x.ltoreq.0.20 and a has the value 1 or 2 and in which Me represents at least one of the alkaline earth metals barium, strontium and calcium. If a = 2 at least 50 gram-atomic % of Me is strontium. If a = 1 up to 25 gram.atomic % of Be together with the same quantity of Si may be replaced by an equiatomic quantity of Al. The luminescent silicate is preferably used in mercury vapor discharge lamps.

Luminescent material

A luminescent beryllium-containing phosphate activated by bivalent europium defined by the formula Me.sub.a-x Be.sub.b Eu.sub.x P.sub.2 O.sub.8 where a + b = 3 and 0.01.ltoreq.x.ltoreq.0.25 and b has the value 1 or 2. If b = 2, Me mainly represents one of the alkaline earth metals barium, strontium and calcium. If b = 1, Me mainly represents barium and/or strontium. The luminescent phosphate may be used in mercury vapor discharge lamps and in low-pressure cadmium vapor discharge lamps.

Beryllium-containing europium activated phosphate phosphor, luminescent

A luminescent screen, particularly for a low-pressure mercury vapor discharge lamp, provided with a luminescent thallium-activated aluminate having the .beta.-alumina structure and defined by the formula (Me.sup.I.sub.1.sub.-x.sub.-p Tl.sub.x Me.sup.II.sub.p) (Al.sub.11.sub.-y Mn.sub.y)O.sub.17 in which Me.sup.I represents at least one of the alkali metals sodium, potassium and rubidium, and in which Me.sup.II represents at least one of the alkaline earth metals calcium, strontium and barium, in which up to 50 mol % of aluminum may be replaced by gallium, and in which

Luminescent screen with thallium activated aluminate

A low-pressure mercury vapour discharge lamp provided with a luminescent coating comprising three luminescent materials each emitting in a narrow spectral range. The first material has an emission band with a maximum between 430 and 490 nm; the second material has its emission in the range 520-565 nm; the third material emits in the range 590-630 nm. The second material is defined by one of the formulas:

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Eindhoven, Netherlands

Judicus M Verstegen