U.S. Philips Corporation

Theo J Popma

Jan Haisma

Hendrik J Joormann

Henricus A Van Hal

Gerhardus A Te Raa

Jacob A Den Boer

Hendrikus J Nabben

Maria G Kamminga-Schrijnemakers

Paul H Joosten

Adrianus T Vink

A radiation conversion screen having sub-layers with mutually different radiation-conversion, radiation-optical and/or technological properties wherein successive sub-layers of luminescent material have a luminescent radiation absorption which decreases in the propagation direction of the radiation beam.

Radiation conversion screen

Luminescent aluminoborate and/or aluminosilicate glass which is activated by one or more rare earth metals. The glass has a matrix comprising from 5 to 65 mol. % of one or more of the alkaline earth metal oxides BaO, SrO, CaO, ZnO and MgO, from 20 to 85 mol. % of B.sub.2 O.sub.3 and/or SiO.sub.2 and from 1 to 35 mol. % of Al.sub.2 O.sub.3. The glass contains as activator Tb.sup.3+ and/or Ce.sup.3+ in a quantity, calculated as Tb.sub.2 O.sub.3 and/or Ce.sub.2 O.sub.3, of 0.1 to 10 mol. % with respect to the matrix. The luminescent glasses have high conversion efficiencies, especially high quantum efficiencies upon UV excitation, and are preferably used in luminescent screens of, for example, discharge lamps or cathode-ray tubes.

Luminescent aluminoborate glass and luminescent screen provided with

Magnesium fluoride layers are obtained by disproportionation of fluorine-containing organic magnesium compounds, notably magnesium trifluoroacetate, magnesium trifluoroacetylacetonate and magnesium hexafluoroacetylacetonate. A solution of such a compound is provided on the substrate in an organic solvent by spinning or dipping at room temperature after which the layer is heated to 500.degree. C. The solution may also be atomized and sprayed on the substrate which is maintained at a temperature of 600.degree. C. It is possible by means of this method to provide pure magnesium fluoride layers at a comparatively low temperature in air and without using film forming vehicles. The MgF.sub.2 layers obtained according to said method are useful as anti-reflective layers on display screens, on optical elements and as components in a multilayer packet, for example a dichroic mirror.

Method of providing magnesium fluoride layers

A conversion screen such as is used for X-ray image intensifier screens, X-ray image intensifier tubes, cathode-ray tubes, image pick-up tubes, X-ray electrography, fluorescent lamps and the like is formed by the deposition of a layer of conversion material on a carrier (19) via a melting space (7) which is preferably heated by means of a plasma arc. This method of deposition offers very robust screens with a high density and also allows the filling of recesses in a carrier with conversion material, so that structured conversion screens can be formed.

Plasma spraying of conversion screens

Method of producing photomasks of X-ray amorphous iron oxide (Fe.sub.2 O.sub.3) by spraying a transparent substrate at a temperature between 180.degree. and 250.degree. C. with a solution of an hydrolysable iron salt in a polar organic solution or, in accordance with a variant of this method, at a temperature between 180.degree. and 750.degree. C. with a solution of a hydrolysable iron salt which also contains a salt of a metal having a greater ion diameter. If temperatures above approximately 230.degree. C. are used, the solvent may in the latter case also consist of water only.

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Eindhoven, Netherlands

Theo J Popma