U.S. Philips Corporation

North American Philips Corporation

Robert John Seymour

Andrew L Dalisa

Joseph Patrick Dougherty

Stewart K Kurtz

An electrophoretic display device comprises a cell in which a colloidal suspension of pigment particles is contained between associated electrodes and means are provided for the establishment of a potential between the electrodes for the selective transport of pigment particles. This potential permits changing the spatial distribution of pigment particles in specifically defined regions of the display cell. The device also comprises a light transmissive plate associated with the cell, whereby illumination received in the plate is internally reflected, with light coupling between the illumination and selected regions of the cell at which such particles are suitably disposed. The coupled illumination is transmitted by the cell to the observer. The cell regions at which the particles are disposed are switchably selectable.

Electrophoretic display devices

A method and device for determining acentricities in a powder material by illuminating the powder with a collimated coherent light beam of given wave-length which generates a second harmonic in the material. The second harmonic with the fundamental removed by filters is divided by a beam splitter and sent to two photomultipliers -- one of which has a narrow band filter to select only light of one wave-length. If all the light is generated at the second harmonic equal signals are produced by the photomultipliers. If non-second harmonic radiation is produced, a larger signal will be produced in the unfiltered reference channel.

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Ossining, NY, United States of America

Robert John Seymour