Abstract: A liquid-filled electro-optic display cell employs an elastomeric diaphragm to seal a filling orifice in the cell side wall. The orifice is surrounded by a rim and the diaphragm is retained over the rim in such a way as to seal the orifice while remaining free to flex over central portions of the orifice. This retention may be effected by means of an annular washer and clamping pin. In this way, sealing is effected and thermal expansion accommodated. The cell is filled by turning it until the orifice is uppermost and filling it until a convex meniscus is formed above the rim to ensure that the diaphragm seals the orifice without introduction of bubbles.

Abstract: An image is displayed in an electrolytic display by the reversible deposition on electrodes having non-scattering surfaces of a deposit having light scattering properties. The deposit scatters incident light out of the specular direction and the image is formed from one only of the specular and non-specular components of the emergent light.

Abstract: A passive display module for use in a display system having a source of illumination and a projection lens includes a liquid filled cell having a transparent top and a wall surrounding a display electrode area. A side light guide, coextensive with the display area, forms or abuts one wall of the cell and directs light from the source onto the display area. The guide has a reflective upper inclined surface for reflecting light onto the display area and for preventing light from the source from escaping directly to the projection lens. A reflective coating is also provided on an outer face of the remaining portion of the cell wall which is inclined inwardly to return escaping light to the system.