Abstract: There is provided a type of luminous hand including a part made of moulded transparent material that forms a circular head (28, 35) and a body (28, 34) of a hand. In order to direct a portion of a light beam parallel to the axis (15) of the hand towards the interior of the body, the head includes a plurality of reflectors (40, 41) distributed around the axis and formed by dihedron shaped hollows. This improves the intensity and uniformity of the light in the hand body. Inclined light-diffusing surfaces, covered with a light coloured paint, are arranged on the bottom face of the hand. In a display device with several coaxial hands (11,12) such as that of a watch, the reflectors of the superposed heads (29, 35) of the hands are located at respective distances from the axis which are different from one hand to another, such that they never completely cover each other. The light source preferably includes three light-emitting diodes (23) located under the dial (10).

Abstract: There is provided a type of luminous hand including a part made of moulded transparent material that forms a circular head (28, 35) and a body (28, 34) of a hand. In order to direct a portion of a light beam parallel to the axis (15) of the hand towards the interior of the body, the head includes a plurality of reflectors (40, 41) distributed around the axis and formed by dihedron shaped hollows. This improves the intensity and uniformity of the light in the hand body. Inclined light-diffusing surfaces, covered with a light coloured paint, are arranged on the bottom face of the hand. In a display device with several coaxial hands (11,12) such as that of a watch, the reflectors of the superposed heads (29, 35) of the hands are located at respective distances from the axis which are different from one hand to another, such that they never completely cover each other. The light source preferably includes three light-emitting diodes (23) located under the dial (10).

Abstract: There is described a colored photovoltaic cell (1) with a semiconductor, preferably silicon, which has high efficiency and a pleasing colored appearance, allowing it to be used as a dial for a watch or another electronic apparatus powered by the cell. The cell includes a reflective metal substrate (2) serving as the bottom electrode, a stack of hydrogenated amorphous silicon layers forming p-i-n junctions (8), and a transparent top electrode (9). The latter may be coated with a layer (16) of slightly diffusing lacquer, which may be colorless or colored. The respective thicknesses e1 of the top electrode and e2 of the silicon are combined as a function of the refractive indices of the materials so as to produce an interferential reflection in a predetermined reflection spectrum.

Abstract: There is described a colored photovoltaic cell (1) with a semiconductor, preferably silicon, which has high efficiency and a pleasing colored appearance, allowing it to be used as a dial for a watch or another electronic apparatus powered by the cell. The cell includes a reflective metal substrate (2) serving as the bottom electrode, a stack of hydrogenated amorphous silicon layers forming p-i-n junctions (8), and a transparent top electrode (9). The latter may be coated with a layer (16) of slightly diffusing lacquer, which may be colorless or colored. The respective thicknesses e1 of the top electrode and e2 of the silicon are combined as a function of the refractive indices of the materials so as to produce an interferential reflection in a predetermined reflection spectrum.

Abstract: A universal timepiece (10) having a manually operable outer ring (33) for selecting one of twenty-four time zones, where a display indicates the time of the time zone selected. For this purpose a device for detecting the rotational position of the outer ring (33) is provided which has a special arrangement of permanent magnets (39a-j) in the outer ring (33) and of magnetic switches (27a-h) in the timepiece casing (11, 12) in a specific number as well as evaluating electronics in the timepiece movement (21). The permanent magnets (39a-j) determine the binary statuses of the magnetic switches (27a-h), which are interpreted together as a signal or as a status pattern. The special arrangement of the magnetic switches (27a-h) and the permanent magnets (39a-j) effect for each rotational position an intrinsic status pattern different in each case from the others which permits a clear indication of the selected rotational position of the outer ring (33).

Abstract: 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.

Abstract: 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.

Abstract: An electro-optic display device having a partially transparent display cell and a semi-transparent mirror located behind said cell and arranged to transmit light waves within a first wave length band and to reflect light waves within a second wave length band. An electro-optic component is located behind the semi-transparent mirror and operates in a third wave length band which overlaps at least partially the first wave length band. The electro-optical component may be a plurality of photo cells used for recharging an accumulator for the display device and/or a light source transmitted across a light plate of frosted or clear glass to illuminate the display cell. The display cell is illuminated by either the reflected light waves or the light waves emitted from the light source.

Abstract: An electronic timepiece provides photo-electric cells disposed behind a passive electro-optic display cell for recharging a storage battery. The timepiece includes in its display a polarizer, a passive electro-optic device such as a liquid crystal, a quarter-wave plate, a cholesteric liquid crystal reflector and photo-electric cell arranged in superposition upon each other. Ambient light passing through the cholesteric reflector is used to energize the photo-electric cells which recharge the storage battery. Ambient light reflected by the cholesteric reflector is used to indicate the displayed information.

Abstract: 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.