Siemens Aktiengesellschaft

Basf Aktiengesellschaft

Guenter Baur

Waldemar Greubel

Hans Krueger

Alois Schauer

Karl-Heinz Etzbach

Peter Neumann

Hans-Werner Schmidt

Helmut Ringsdorf

Matthias Dust

Rudolf Knauer

Hans Kohlmueller

Friedrich Windscheid

Rudolf Kiefer

An optical recording medium contains, on a base, one or more dyes and a polymer which forms liquid-crystalline phases. The information is written into the uniformly oriented liquid-crystalline polymer layer, for example by means of a laser. During this procedure, the polymer heats up locally to above a phase transition temperature. By cooling, the resulting change is frozen in the glass state. The information can be erased by applying an electric field and/or heating. The recording material permits high-contrast storage and possesses high sensitivity, good resolution and excellent stability.

Optical recording medium

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

A display device and a method of using the display device characterized by a light trap which includes a member consisting of a material having an index of refraction greater than one and containing fluorescent particles and which light trap collects impinging ambient light by means of fluorescent scattering by the particles and subsequent reflection of the collected light on the boundary surfaces, a plurality of electrodes disposed adjacent the surface of the light trap at selected portions of the surface and a fluid being provided adjacent each of the electrodes so that an application of voltage to selected electrodes causes a precipitate to be formed from the fluid and collected adjacent the selected electrode to create an optical indication and the application of a counter voltage at the selected location causes an erasing of the indication by eliminating the precipitate and placing it back into the fluid. The precipitate may be separated from the fluid by an electrochemical process which may be either a metallic material or an organic electrochromic. The fluid may also be a suspension of particles which particles will be transported to a given location by the application of an appropriate voltage.

Display device for optically representing information and a method of

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

An arrangement or device for optical transmission of communications including a light transmitter with an associated receiver characterized by the receiver having a light collecting body having an index of refraction greater than 1 and containing fluorescent materials which absorb the band of light emitted by the transmitter and create a band of light which is not absorbed by the substance and is detected by the receiver. If more than one transmitter is utilized, they are arranged to transmit in different frequency bands and each transmitter has an associated fluorescent substance which will absorb the discrete separate frequency but not the other frequency bands and emit a fluorescent signal which is only detected by the respective receiver for that transmitter. These fluorescent substances can be in separate light collecting bodies or as a mixture in a single body which has more than one receiver attached thereto.

Arrangement for optical transmission of communications

Electro-optical display device which may operate either in a one or multi-color mode and utilizes electro-optical light valves for controlling transmittance of a passive light through the device characterized by passively amplifying the brightness of the display device with the addition of a light trap which includes a fluorescent plate having mirrored edge surfaces. While the invention or improvement may be utilized with any passive optical display device, it is particularly useful with a liquid crystal display device.

Electro-optical display device with electro-optical light valves

An indicating device for projecting symbols of all kinds characterized by a plate of fluorescent synthetic material having metallized edges to create a light trap for the fluorescent light created in the plate, a layer of light dispersing material mounted in spaced relation to a surface of the plate, contact film disposed at least in selected areas between the layer and plate, means for selectively moving portions of the layer into optical contact with the contact film and plate to cause decoupling of the fluorescent light from the plate. The means for moving includes a plurality of electrodes disposed in the device in a given pattern and means for selectively applying an electrical current to the electrodes to create a selective arrangement of electrical fields to create a display of a desired symbol. The means for moving may be a membrane on which electrodes are disposed to coact with electrodes on the plate to deflect the membrane toward the plate to move the dispersing layer into optical contact with the plate or may be a ceramic plate of ferroelectric material which on the application of electrical current to the electrodes causes a selected expansion of the plate due to remanent electrical polarization to move the layer into contact with the plate of fluorescent synthetic material.

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Freiburg, Germany

Guenter Baur