Hewlett-packard Development Company, L.P.

Susanne Klein

Adrian Derek Geisow

A liquid crystal display device comprises a layer of liquid crystal material () between spaced-apart cell walls (), and electrodes () provided on at least one cell wall for applying an electric field across at least a part of said liquid crystal material. The liquid crystal material has anisotropic light-absorbing particles dispersed therein and substantially aligned therewith. The invention also provides a composition for use in the display.

Liquid crystal display device

The present invention relates to display, in particular to a liquid crystal display illuminated by ambient light. The display has a display area, and a light guide system for providing light to the display area, the light guide system comprising: a planar light guiding layer comprised of liquid crystal material and having a light emitting surface and a plurality of side faces disposed around the light emitting surface; a plurality of light pipes, each light pipe having a collector end for collecting ambient light and an output end, the output ends being arranged along the side faces of the light guiding layer so as to introduce the collected light into the guiding medium. The output ends of the light pipes are distributed evenly along each side face of the light guiding layer so as to provide homogeneous illumination to the display area.

Liquid crystal display having light pipe illumination

The present invention relates to the measurement of birefringence, particularly the optical characterization of retardation and eigenpolarization of an unknown retarding device ( ). An optical probe beam ( ) with a pre-determined polarization ( ) is split into two components ( ), with constant dynamic phase difference. The beam components ( ) pass through the retarding device ( ) in opposite directions so that the polarization of each probe beam component ( ) is retarded by an equal degree. Then, the retarded probe beam components ( ) together pass through a polarizing analyzer ( ) with a pre-determined polarization axis to resolve the polarization of each retarded probe beam component ( ) along said axis. The polarization resolved beams ( ) combine on an optical detector ( ) so that the beams maintain the same dynamic phase and interfere coherently depending on the geometric phase between the two beams ( ). The analyzer ( ) is rotated to resolve the polarization of each of the polarization resolved beams ( ) along its rotating axis, in order to vary the geometric phase and hence the measured interference from the detector ( ). The measured varying interference is used to calculate the retardation and eigenpolarization of the retarding device ( ).

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Bristol, United Kingdom

Susanne Klein