Display device comprising a liquid crystal cell with light valves

US4240711A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Gunter Baur · Glückstadt, DE
• Waldemar Greubel · Munich, DE
• Hans Kruger · Birkenfeld, DE
• Alois Schauer · Kleinmachnow, DE

Key dates

• Filing date: Feb 13, 1978
• Grant date: Dec 23, 1980
• Expiry date: Feb 13, 1998

Classification

• Technology area (CPC G): Physics
• CPC primary: G02F1/13725
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

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.