Ebauches S.a.

Asulab S.a.

Asulab S.a. - Eta 72

Fereydoun Gharadjedaghi

Yves Ruedin

Rene Viennet

Eric Saurer

Claude Laesser

Bernard Le Fur

Jean-Francois Guyenet

The column electrodes of the display device are each formed by an alignment of conducting areas which are electrically connected to each other and which are spaced from each other, while disposed between two successive conducting areas of each electrode, in alignment with said conducting areas is a conducting area of an adjoining electrode. n+1 different reference signals are produced such that the effective value of the difference between two different signals is sufficient to generate an electro-optical effect. The first n signals of said signals are each applied to a line electrode. A signal selected from the above-mentioned n+1 signals is applied to each column electrode said selection being made in dependence on the value of a control signal.

Electro-optical display device of point matrix type

A watch display comprises time display hands (3, 4) and a reflecting digital display (5) which acts as dial for the hands, the display being transparent under the effect of an electric field and opaque in the absence of the field.

Watch with an analog display device the dial of which is formed by a

An electro-optic passive display device comprising a pair of plates having, as an active component between the plates, a mixture comprising a nematic liquid crystal possessing negative dielectric anisotropy, dichroic molecules and a chiralic compound capable of providing a helical structure to the active component, the chiralic compound concentration being selected to produce a pitch of the helix between 0.9d and 3d, 'd' being the distance between plates, critical to ensure the formation of a helical structure only under the effect of an electric field and to provide a high contrast display.

Electro-optic passive display cell

Electro-optic passive display cell constituted by a layer of a mixture of a nematic liquid crystal having a positive dielectric anisotropy, an optically active compound and dichroic molecules. The inner faces of the plates of the cell are covered with alignment layers such that, in the area situated outside the display zones or segments, the layer of the mixture has a homeotropic structure in its whole thickness. Opposite the segments the cell is arranged in such a way that the layer of the mixture has a helicoidal structure so that incident light is absorbed in these zones when the segments are not activated and that the layer of the mixture is orientated according to a homeotropic structure under the action of an electric field. Thus, when the cell is at rest, all its segments are visible. The display is effected by 'cancelling' or 'effacing' the segments which must not appear, so that only the non activated segments remaining visible in dark on a clear or transparent background.

Two alignment films are deposited on a liquid crystal substrate. Each film is deposited at an angle of about 5.degree. with respect to the substrate surface. The projection on the substrate of one deposition beam forms an angle of 180.degree. with the projecton on the surface of the other deposition beam. The resultant liquid crystal cell has a sharp threshold with good contrast, particularly for multiplexing applications.

Liquid crystal alignment layers

A liquid crystal alignment film is deposited on the inner surfaces of two plates of an electro-optic passive display cell. The film is vacuum evaporated on the plates at an incidence of 5.degree. and at least one plate is rubbed in only the direction of deposition. A helicoidal nematic liquid crystal is disposed between the two plates of the cell, and is aligned by the film.

Method of manufacture of a passive electro-optic display cell having an

An electro-optic passive display device displays information in dark characters on a light background during the day, and in light characters on a dark background during the night. The device has a polarizer, an electro-optic display cell, a quarter-wave plate, a chloesteric liquid crystal cell and an illuminator arranged in superposition on each other. These elements control the polarization of light transmitted through the device which polarization causes the changing of the displayed information from dark characters on a light background to light characters on a dark background.

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Neuchatel, Switzerland

Fereydoun Gharadjedaghi