Abstract: An optical element comprises a transparent substrate. An antireflection coating is provided on the substrate for reducing reflections of wavelengths from approximately 700 nm to approximately 1700 nm. The coating comprises a plurality of stacked, uniform layers with refractive indices which decrease toward the top of the stack. A base coating is arranged between the layer stack and the substrate. The effective refractive index at the top of the base coating is at least 2.5, and the base coating is a graded index layer.

Abstract: A monocrystalline layer of one semiconductor material is grown onto a surface of a monocrystalline semiconductor body by means of molecular beam epitaxy. During such growth, the semiconductor body is kept at such a low temperature that a non-monocrystalline layer is obtained. The non-monocrystalline layer is then converted by a heat treatment into a monocrystalline form. Accordingly, an abrupt junction between the two semiconductor materials is obtained.

Abstract: In a tunable Fabry-Perot interferometer, the supports for two parallel mirrors consist of bundles of optical fibers with the mirrors being provided on the ends of the fibers. This structure may be used advantageously in an X-ray display device wherein the structure is located between the display screen on which the visible X-ray image is displayed and a television camera tube. By using the Fabry-Perot interferometer as a light attenuator in such a device, problems where the camera tube is overridden when making an X-ray record can be prevented by causing the reflection coefficient of the mirrors in the visible range of the spectrum to be 99% or more. Also, the half width of the transmission wavelength pass-band of the Fabry-Perot interferometer can be made less than 50 nm.

Abstract: 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.

Abstract: A method of and a device for high-precision moulding of transparent objects is described. Before the object assumes its final shape, a radiation beam is passed through the moulds of a moulding device and the material contained therein, and the intensity distribution of the radiation spot formed by the beam is compared with a reference, thereby enabling the moulds to be aligned very accurately, so that high-quality products can be manufactured.

Abstract: Glasses consisting of 45-55 mol. % P.sub.2 O.sub.5, 15-40 mol. % BaO, 5-15 mol. % Li.sub.2 O, 5-35 mol. % PbO, 0-2 mol. % Al.sub.2 O.sub.3 and 0-6 mol. % F are suitable for the precision pressing of lenses.

Abstract: Glass objects, lenses in particular, can be pressed with precision from a glass which contains 45-55 mol. % P.sub.2 O.sub.5, 15-40 mol. % BaO, 5-15 mol. % Li.sub.2 O, 5-35 mol. % PbO, 0-2 mol. % Al.sub.2 O.sub.3 and 0-6 mol. % F.

Abstract: Glass objects, lenses in particular, can be pressed with precision from a glass which contains 45-55 mol. % P.sub.2 O.sub.5, 15-40 mol. % BaO, 5-15 mol. % Li.sub.2 O, 5-35 mol. % PbO, 0-2 mol. % Al.sub.2 O.sub.3 and 0-6 mol. % F. A cube of glass is made from the above composition and preheated to a temperature of 20.degree.-60.degree. C. above the American softening point to obtain a polishing effect. The preheated cube is then inserted into preheated dies which are closed to form a precision pressed object of the glass.

Abstract: The objective comprises a plurality of movable lens components and at least one stationary lens component group, at least two of said components including an aspherical surface. The movable components are constituted by single lenses of which at least one lens comprises an aspherical surface, while the stationary lens component group(s) may comprise at least one aspherical surface. Steadiness of the image plane is obtained by mechanical compensation for focal-length variations with a ratio greater than five, which may readily reach the value eight. The aspherical lenses are arranged so that for the same focal length variation the total number of lenses of the objective, which may be spherical or non-spherical, is smaller than in any other variable-focus objective with a stationary image plane comprising solely spherical lenses:This results in a reduction of the mass of the objective, namely of the movable parts, and a reduction of the power necessary for moving said parts.

Abstract: A lens having a spherical surface and an aspherical surface curved relative to each other to minimize coma for a large diffraction-limited field and a large numerical aperture.

Abstract: A method for the manufacture of a mould intended for the precision moulding of glass articles, notably aspherical lenses. The desired shape and dimensional accuracy are imparted to a mechanically treated preform by an accurate polishing operation. Subsequently, the polished preform is prestressed and reinforced by a chemothermal treatment. The surface of the mould thus obtained comprises an edge zone which is subject to compressive stress and which changes over, via a neutral stress-free zone, to the core which is subject to tensile stress. The mould in accordance with the invention has a longer life and produces moulded products having a quality which is higher than that of products made by means of known moulds.

Abstract: By using special dies, lenses from glass can be manufactured with great precision. Such dies are manufactured from quartz glass. Quartz glass can be worked with the required shape accuracy and the required smoothness, for example, by a polishing treatment succeeded by sputtering.

Abstract: Glass objects, lenses in particular, can be pressed with precision from a glass which contains 45-55 mol. % P.sub.2 O.sub.5, 15-40 mol. % BaO, 5-15 mol. % Li.sub.2 O, 5-35 mol. % PbO, 0-2 mol. % Al.sub.2 O.sub.3 and 0-6 mol. % F.

Abstract: A method and device are provided for machining transparent glass and vitreous material by means of a single point cutting tool. A portion of the workpiece to be worked is heated integrally and uniformly by a first heat supply, which is spread along the workpiece, to the softening temperature, and simultaneously the surface to be worked is locally heated in the region of the cutting area at the moment of material removal to a depth equal to the cutting depth by a second concentrated heat supply which is superimposed on the first heat supply. All this is provided in such a manner that a turning operation, as well as simultaneously therewith and immediately thereafter a relaxed flow of the work surface, takes place. By means of the method according to the invention, it is possible to turn workpieces of glass and vitreous materials so that the work surface has a high dimensional accuracy, as well as an optical surface quality in particular, such as a smooth and transparent surface.

Abstract: A magnetic device comprising at least one thin domain layer of a magnetizable material which has an easy axis of magnetization which is substantially normal to the surface of the layer and in which magnetic domains are propagated under the influence of a bipolar current, for example an alternating current, by a pattern of electrically conductive material with which the layer is provided. Elements are furthermore present which cause an asymmetry force and thus determine the direction in which the domains are propagated. The electrically conductive material and the elements are present in a single pattern which is constructed from at least a layer of magnetic material.

Abstract: A device for storing digital information in the form of magnetic domains including at least two ferrimagnetic layers on a substrate. The ferrimagnetic layers are separated by a compensation wall and in the presence of a bias magnetic field single magnetic domains and superposed magnetic domain pairs, the superposed domains being separated by a compensation wall, are generated. All single and superposed domains are mutually repulsive. The domains within a superposed pair are attracted to each other. The generated domains are propagated to a shift register and when the reigster is filled a row of domains is coincidentally propagated, transversely out of the register, to a domain array region adjacent the register. Rows are then propagated through the array region to a second shift register where they are individually detected and annihilated. A control device assures the proper working relationship between all elements.

Abstract: A magnetic bubble device comprising a non-magnetic substrate layer, and a sequence of magnetic layers joined to each other and to the magnetic substrate layer, e.g. by epitaxial growing of crystalline layers, whereby at least two of the magnetic layers may accommodate magnetic bubbles which are stably joined through an interlayer magnetic compensation wall, or by an essentially finite potential barrier.

Abstract: A method of manufacturing a magnetizable layer having domains with at most two Bloch walls for a magnetic domain device in which a monocrystalline layer of Y.sub.3.sub.-x La.sub.x Fe.sub.5.sub.-Y Ga.sub.Y O.sub.12, wherein 0.1 .ltoreq. .times. .ltoreq. 0.2 and 1.0 .ltoreq. Y .ltoreq. 1.5 is provided on a monocrystalline substrate and is covered with an SiO-containing layer after which the monocrystalline layer is maintained at a temperature between 300.degree. C and 600.degree. C for some time.