At&t Bell Laboratories

Brandeis University

Robert B Meyer

Gary D Boyd

Julian Cheng

Jayantilal S Patel

Robert N Thurston

A flash camera with glare controlling ability for general photographic use is described. It includes at least two panchromatic reflective sheet polarizing filters. One filter is incorporated in the flash unit to produce a polarized light flash source. The flash source also incorporates light redirecting means such that a majority of light from the flash is directed toward the photographic scene. A second filter over the camera lens excludes that light originating from the flash source which is specularly reflected from the photographic scene.

Color-balanced glare reduction system for flash cameras

A liquid crystal device includes a liquid crystal material (30) in which the molecules (15) form a helix having its axis essentially parallel to the plates (13, 20) of the device. A suitable electric field (E), applied essentially perpendicular to the plates, causes planes of the directors (n) to rotate about the field direction to an acute angle .phi. with respect to the helix axis, thereby inducing alternating bands of splay and bend in the material. Such configurations, which have polar symmetry, give rise to the flexoelectric effect in which the polarization (P) of the molecules tends to be parallel to the applied field, and the magnitude of the field is linearly related to tan .phi.. The ability to rotate the directors means that the optical properties of the material can be changed.

Flexoelectric liquid crystal device

A bistable nematic liquid crystal display cell is electrically switched between topologically equivalent, asymmetric horizontal states. Switching is initiated by application of a symmetry breaking field such as a DC electric field of a predetermined polarity. An AC electric potential is then applied across the cell to complete the switching cycle and maintain the state. The cell includes upper and lower parallel substrates, upper and lower topographically textured tilt alignment surfaces on the corresponding substrates, and nematic liquid crystal material between the substrates. In an active region of the cell, the tilt alignment surfaces form an equal reverse tilt boundary condition. In an isolation region surrounding the active region of the cell, the tilt alignment surfaces are formed to have a parallel tilt boundary condition.

Nematic liquid crystal storage display device

A bistable nematic liquid crystal display cell is switched between topologically equivalent, asymmetric horizontal states. Switching is initiated by application of a directional, symmetry breaking field such as a transverse magnetic field. An electric potential is then applied across the cell to complete the switching cycle and maintain the state. The cell includes upper and lower parallel substrates, upper and lower topographically textured tilt alignment surfaces on the corresponding substrates, and nematic liquid crystal material between the substrates. In an active region of the cell, the tilt alignment surfaces form an equal reverse tilt boundary condition. In an isolation region surrounding the active region of the cell, the tilt alignment surfaces form a parallel tilt boundary condition.

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Wellesley, MA, United States of America

Robert B Meyer