U.S. Philips Corporation

Roelof Egbert Schuil

Constant J Geenen

Jan L Van Koesveld

The invention relates to a protective package for a display window for a display tube, which display window has an upstanding edge. A cover such as a second display window is laid on a synthetic resin ring located on the upstanding edge, and the space which is enclosed by the display window 2 and the cover is evacuated.

Protective package for a display tube window

A display tube comprising in an evacuated envelope means to generate at least one electron beam which is focused on a display screen and describes a field thereon, which display screen comprises a terbium-activated blue-luminescing phosphor on a carrier, and in which the light emitted by the phosphor falls through a filter. If the energy of the emissions of the phosphor which find their origin in the .sup.5 D.sub.3 -level of terbium is at least 40% of the energy of the emissions of all terbium levels and the filter has a transmission of more than 75% at those wavelengths where the .sup.5 D.sub.3 .fwdarw..sup.7 F.sub.5 and the .sup.5 D.sub.3 .fwdarw..sup.7 F.sub.4 emissions of terbium are located and the filter has a transmission of less than 10% at those wavelengths where the .sup.5 D.sub.4 .fwdarw..sup.7 F.sub.5 and the .sup.5 D.sub.4 .fwdarw..sup.7 F.sub.4 and the .sup.5 D.sub.4 .fwdarw..sup.7 F.sub.3 emissions of terbium are located so that the color point of the filtered light is located in the range x.ltoreq. 0.200 and y.ltoreq.0.100 in the CIE color triangle, a well saturated blue picture is displayed having a satisfactorily high energy efficiency.

Display tube with terbium-activated blue-luminescing phosphor screen

A method of manufacturing a rare-earth aluminate, particularly a luminescent rare-earth aluminate, in which a starting mixture of the composite oxides or of compounds producing these oxides at an elevated temperature together with a flux is heated at a high temperature. At least one of the compounds rubidium fluoride, cesium fluoride and potassium fluoride is used as a flux.

Method of manufacturing a cerium activated luminescent rare-earth

A shadow mask tube having phosphor regions with negative tolerance, and the intermediate spaces between the phosphor regions on the face plate being devoid of usual light-absorbing material and the aluminum layer.

Color screen with space between luminescent regions pervious to thermal

A cathode-ray tube particularly for flying spot scanners, provided with a luminescent silicate activated by cerium, defined by the formula Li.sub.1-x Na.sub.x Y.sub.1-p Ce.sub.p SiO.sub.4, in which 0 .ltoreq. x .ltoreq. 0.90 and 0.0001 .ltoreq. p .ltoreq. 0.25, which silicate has the olivine crystal structure.

Cathode-ray tube provided with a luminescent silicate

A cathodochromic sodalite defined by the formula Na.sub.3 Al.sub.3 Si.sub.3 O.sub.12.NaX (X = Cl, Br or J) comprising at least one of the elements tin, lead and germanium in a quantity of between 0.05 and 2 atom % calculated with respect to silicon. The addition of the said elements results in an improvement of the reversible bleaching properties. Notably, a faster and also a more complete bleaching is obtained.

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Eindhoven, Netherlands

Roelof Egbert Schuil