Abstract: The specification describes a two-dimensional symbol code for representing binary data, which symbol code is constructed from a plurality of graphical symbols arranged next to one another, wherein the symbol code is formed from precisely two different symbols having the same surface area which differ in their areal brightness distribution and each code a value from a binary data word. The symbols have a complementary brightness distribution. In a method for reading this two-dimensional system code, the system code has a filter applied to it which matches the brightness distribution of one of the two complementary symbols, wherein in the event of a match one symbol is recognized and in the event of no match the other symbol is recognized.

Abstract: A method for producing a self-supporting thick-film structure on a substrate above a recess defined in the substrate, includes applying an active layer onto an auxiliary substrate; positioning the active layer in contact with the substrate and above the recess defined in the substrate; firing the substrate to bond the active layer thereto; and separating the active layer bonded to the substrate from the auxiliary substrate, wherein the active layer has a thermal expansion coefficient which is less than that of the substrate so that a self-supporting thick-film structure is formed above the recess.

Abstract: In a process for manufacturing a circuit including a first circuit plane of a ceramic substrate which is covered with, for example, thick-film structures and is imprinted with corresponding conductor paths having contact faces, the ceramic substrate is to be connected with a second circuit plane composed of a green tape substrate.

Abstract: A free-standing, self-supporting layer of glass-ceramic or crystallized glass is applied by thick-film technology over a presintered layer made of a vaporizable or etchable material which, after sintering the thick-flim glass-ceramic or crystallized glass layer (3) to a substrate (1), is removed by heating or etching. The layer (2) to be removed is preferably applied in paste form with the glass-ceramic thick-film layer (3) thereover either in form of a crossing bridge, as a partially covering cantilever, or entirely surrounding the layer 2, in which latter case the thick-film layer (3) is of porous construction so that the volatile or vaporizable components of the underlying layer (2) can escape through the thick-film layer (3). A typical layer which is volatile or vaporizable includes carbon black, a resin binder and a solvent, applied to a substrate, for example of ceramic or enameled metal, over which the glass-ceramic layer is applied.

Abstract: The high pressure sensor includes a housing part, a lid closing the same and an intermediary disposed sensor disk. A cylindrical pressure chamber is formed in the housing, wherein an inner area of the sensor disk is disposed in a sealed off manner. In this area the measuring sensors are disposed in form of piezoresistive layer resistors. Layer conductors penetrate from this inner area into an outer area, wherein evaluation circuits and the evaluation electronic are disposed. The total sensor disk is provided with one or a plurality of glass layers in such a manner that a flat surface is obtained. Pressure changes of the pressure medium are picked up in the pressure chamber by the measuring sensors and are processed accordingly. Such a high pressure sensor is relatively simple and advantageous in its use.

Abstract: Very fine solder-coated conduction paths are made on ceramic, glass or enamel substrates by the combination of a first step in thick-film technology followed by the photo-masking and etching steps typical of thin-film technology, after which galvanic reinforcement of the initial calcined copper paste layer is performed in the locations where the initial layer is exposed by the developed mask. A lead-tin solder layer is then galvanically deposited, which is thicker than the mask, after which the mask is removed and the newly exposed portions of the initial copper layer are etched away. A reflow treatment of the solder layer pattern consolidates the solder layer by melting on top of the boundaries of the unetched initial copper layer. It is possible to obtain conduction path spacings down to 50 .mu.m with conduction paths coated with solder that have excellent adhesion to ceramic, glass or enamel substrates.

Abstract: The invention relates to hexa-substituted tribenzocyclononatriene derivats constituting a new type of liquid crystals with novel "pyramidal" mesophases. The compounds of the invention differ from the known liquid crystals in their different steric molecular structure. Their molecules consist of a rigid central nucleus of pyramidal structure, the chains of substituents being symmetrically attached to the basis of the pyramid. The compounds of the invention have an electric dipole moment and can be excited in the electric field. Therefore, they are suitable for use in memory devices and/or electro-optical display means.

Abstract: A free-standing, self-supporting layer of glass-ceramic or crystallized glass is applied by thick-film technology over a presintered layer made of a vaporizable or etchable material which, after sintering the thick-film glass-ceramic or crystallized glass layer (3) to a substrate (1), is removed by heating or etching. The layer (2) to be removed is preferably applied in past form with the glass-ceramic thick-film layer (3) thereover either in form of a crossing bridge, as a partially covering cantilever, or entirely surrounding the layer 2, in which latter case the thick-vaporizable film layer (3) is of porous construction so that the volatile or components of the underlying layer (2) can escape through the thick-film layer (3). A typical layer which is volatile or vaporizable includes carbon black, a resin binder and a solvent, applied to a substrate, for example of ceramic or enameled metal, over which the glass-ceramic layer is applied.