Abstract: An optical information disk in which information can be written and read optically and which has a substrate plate which on at least one side has a recording layer which satisfies the formula Te.sub.x Se.sub.y Sb.sub.z S.sub.q wherein x=55-85 at. %, y=13-30 at. % z=1-12 at. %, q=0-10 at. % and x+y+z+q=100. Suitable recording layers are Te.sub.60 Se.sub.25 Sb.sub.10 S.sub.5 and Te.sub.75 Se.sub.15 Sb.sub.5 S.sub.5.

Abstract: The invention relates to an optical recording device having a substrate plate which is provided on at least one side with a first ablative recording layer and a second ablative recording layer provided hereon, the second ablative recording layer having a higher surface energy than the second ablative recording layer. Both recording layers preferably comprise the same common metal, for example tellurium.

Abstract: The invention provides an information-recording element in which information can be written and read optically. The element is constructed from a transparent substrate, a laser light-absorbing, dye-containing auxiliary layer provided thereon, as well as a laser light-reflecting recording layer present on the auxiliary layer. Upon recording information the element is exposed to pulsated laser light via the substrate, holes being formed in the recording layer. The auxiliary layer stimulates the formation of holes, a saving of laser light energy being obtained. In a favorable embodiment the auxiliary layer has a laser light absorption of from 20 to 80% and a maximum thickness of 2500 A. In a further favorable embodiment the auxiliary layer also comprises an endothermal material, for example, nitrocellulose having a nitrogen content of at least 11%.

Abstract: A dispenser cathode comprising a porous metal body which has an emissive surface and the pores of which contain one or more compounds for dispensing at least barium and scandium to the emissive surface, which compounds are composed of at least barium oxide, scandium oxide and aluminium oxide, in which the quantity of scandium oxide is less than 10% by weight, and preferably 3% by weight, of the overall quantity of the dispensing compound (s), has substantially the same good emissive properties as cathodes in which the dispensing compound comprises 5.5% by weight of scandium oxide and 18% by weight of yttrium oxide (Y.sub.2 O.sub.3), or barium scandate as a dispensing compound.