Siemens Aktiengesellschaft

Alois Schauer

Hans Krueger

Waldemar Greubel

Guenter Baur

Manfred Roschy

Hans Kruger

Gunter Baur

Helmold Kausche

Karl-Heinz Walter

Wilfried Juergens

A display device for displaying bright images on a dark background, which device includes a liquid crystal cell having a liquid crystal layer with switchable zones between at least two optical states, a light trap in the form of a body exhibiting fluorescent particles and having light emergent windows disposed behind each of the switchable zones in the direction of observation, characterized with the liquid crystal layer containing at least one pleochroic dye. The dye in the liquid crystal layer acting by itself or in conjunction with a polarizer can block passage of the fluorescent light during one optical state of the layer and enable passage of the light during the other state.

Display device for displaying light images on a dark background

The present invention is directed to a process and display for producing an image in front of an optically contrasting background. The display installation is characterized by a preferably but not necessarily, plate-shaped body having exit windows for emitting light in given areas and light valves associated with each of the exit windows for controlling the light being emitted therefrom. The light valves include filters which have an absorption frequency range and the plate member emits light from the exit windows in an emission frequency range. One of the members, either the filter member or the plate member, can have its associated frequency range shifted by the application of an electrical field so that light can pass through the filter without being absorbed or is absorbed by the filter.

Process and apparatus for displaying an image in front of an optical

A display device for representation of a bright image on a background which device has a light valve comprising a liquid crystal cell having a medium which can be switched zone-wise between at least two optical states and a light trap or body which consists of a material having an index of refraction greater than 1, contains a fluorescent material, and is provided with an outlet window for each of the switchable zones characterized by means coacting with the switchable medium to control the passage of the light through the device so that in a rest or inactive state of the medium, the medium and means allow the passage of the excitation light for the fluorescent particles and the passage of the fluorescent light therefrom and in an 'on' or activated state of the medium, the means and medium are impermeable at least to the fluorescent light so that each of the switchable zones of the medium is placed in an 'on' state only when it belongs to the background of the image. The means may be a pleochroic dye operating with a single polarizer or a pair of cross polarizers, which cooperate with the material of the liquid crystal which forms a twisted cell.

Display device for the representation of bright images on a dark

A display device having a liquid crystal cell containing a medium, which can be switched zone-wise between at least two different optical states to form a light valve, a light trap in the form of a plate-shaped body disposed behind the liquid crystal cell when taken in a direction of observation of the device, the plate-shaped body having a material with an index of refraction greater than 1, containing fluorescent particles, and possessing a light emergent or outlet window at the rear of each switchable zone of the liquid crystal cell characterized by the light emergent or outlet windows comprising a groove in the plate and a light scattering surface disposed between the groove and the medium of the liquid crystal cell. Preferably, the grooves of each of the windows is disposed in a rear surface or side of the fluorescent plate and the scattering surface is arranged on a front surface of the plate and can either be formed by a pigment layer which has been silk screened on the front surface or a rough surface zone which has been embossed on the front surface.

Display device comprising a liquid crystal cell with light valves

A thin-film circuit which includes temperature-compensated RC elements consisting of an AlTa alloy layer having approximately 3-17 at % tantalum in aluminum, which is sputtered or vapor deposited onto a non-conductive substrate, is produced by a process in which the AlTa alloy layer is deposited in an operative, reactive gas mixture, containing at least one of the gases O.sub.2, CO.sub.2, and N.sub.2 and the TC.sub.R value is established by the tantalum component of the alloy layer and/or partial pressure of the reactive gas, and the TC.sub.C value of the capacitors formed from the AlTa alloy layer is established by tempering to be at least approximately oppositely equal to the TC.sub.R value.

Process for the production of a thin-film circuit

A thin film circuit consisting of a planar substrate of insulating material and a thin metal film formed from an alloy of aluminum with between 2 to 20 atom percent tantalum from which resistors and capacitors are developed. The metal film has an equivalent composition to a film which is formed by means of reactive cathode sputtering. In particular, the film is equivalent to a film formed using a cathode of aluminum and tantalum which is reactively sputtered in a sputtering atmosphere containing oxygten with a low partial pressure.In such an arrangement, the temperature coefficient of resistance and the capacity temperature coefficient compensate one another. The alloy films have a high oxidation stability and the resistors and capacitors therefrom have a high resistance to aging.

Thin film circuit

Al-Ta alloy films containing 2 to 20 atomic % of Ta in Al exhibit an improved temperature stability. An Al-alloy film containing 7 atomic % of Ta has a resistivity of 60.mu..OMEGA. cm, a temperature coefficient of resistance of +100 ppm.degree./K and a sparking potential of about 400 V when anodizing in 0.1% H.sub.3 PO.sub.4. An Al-alloy film containing 15 atomic % of Ta has a specific resistance of 200.mu..OMEGA. cm, a temperature coefficient of resistance of -100 ppm.degree./K and a sparking potential of about 300 V when anodizing in 0.1% H.sub.3 PO.sub.4. The alloy films are applied on a non-conductive substrate, as by RF-cathode sputtering in a desired thickness and are useful for thin-film circuits, discrete resistors, capacitors, etc.

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Gruenwald, Germany

Alois Schauer