U.S. Philips Corporation

Joannes L Van De Venne

Ties S Te Velde

Hendrik Veenviliet

A passive display device comprising a first and a second supporting plate at least one of which is transparent, a number of display elements for controlling the reflection or transmission of light each having at least one fixed electrode and an electrode which is movable with respect to said electrode by electrostatic forces and which is kept separated from the fixed electrode by means of at least one electrically insulating oxidic layer, the insulating oxidic layer comprising a layer of a compound which comprises a polar and a non-polar group and the polar group of which is adsorbed or linked to the surface of the insulating oxidic layer.

Passive display device

A layer of liquid crystal is present between two supporting plates with a large number of picture electrodes arranged in rows and columns on at least one of the supporting plates. Strip-shaped row electrodes and strip-shaped column electrodes are provided between the respective rows and columns of the picture electrodes. The picture electrodes arranged in rows can be contacted with a respective row electrode by way of at least one micromechanical leaf spring which provides the liquid crystal with a sufficiently steep threshold with respect to the applied voltage, and provides the liquid crystal with a memory when the picture electrodes form picture elements of a display device. Because of this arrangement, the number of lines to be driven of the display device can be extended.

Display device with micromechanical leaf spring switches

Picture display cell having a liquid crystalline compound provided between two substrate plates comprising at their inner surfaces electrodes and a monolayer of a monofunctional silane compound with which a homeotropic orientation of the liquid crystalline compound is obtained.

Picture display cell

In order to provide a passive electro-optical display medium in a matrix display device with a sufficiently steep threshold with respect to the applied voltage and having a memory, a switching element (9) is placed in series having each picture element. The switching element (9) is provided between a picture electrode (6) of each picture element and a driving electrode (8). The switching element (9) is formed by a polysilicon island (20) in which n.sup.+ -doped regions (22,23) are provided which are separated by a p-doped region (21). As a result of this, two series-arranged, oppositely directed p-n junctions are formed of which one is always reverse biased. The width of the p-doped regions is so small that punch-through occurs between the two p-n junctions before one of the p-n junctions breaks down. Due to the occurrence of punch-through, the series resistance of the switching element is negligibly small so that a favorable R.sub.ON /R.sub.OFF ratio is obtained and the picture elements can be driven with comparatively low voltages.

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Eindhoven, Netherlands

Joannes L Van De Venne