Qinetiq Limited

F. Poszat Hu, LLC

Holographic Imaging LLC

Other

Richard Jonathan Miller

Mark Anthony Gleeson Smith

John Clifford Jones

Maurice Stanley

Victor Chaklam Hui

Jonathan Rennie Hughes

Isabelle Marianne Votte

Jonathan R Hughes

In a liquid crystal device a substrate () favors at least two stable or metastable differently directed liquid crystal alignments, and switching means for causing the liquid crystal material to switch between the alignments includes means arranged for optically irradiating said device. The latter may provide linearly polarized light () for inducing a torque on the liquid crystal to determine the alignment direction, and may optionally cooperate with a second energy supplying means such as an electric field (V) for assisting and switching. Alternatively, the alignment of the liquid crystal may be switched by a second energy supplying means such as an electric field, the light serving to produce heat to aid the switching. Either or both energy sources may be applied locally for switching of selected areas or pixels. Energy levels at the bistable substrate may be adjusted by the use of an oligomeric additive (slippery surface). As shown, the alignment at the surface of an opposed substrate () optionally follows the alignment at substrate ().

Bistable liquid crystal devices

The present invention relates, in one aspect to an image replication system comprising a light guide (), a light source () arranged to direct emitted light into the first end (a) of a light guide (), a reflective spatial light modulator () and focussing means (). In a preferred embodiment, the light guide () is in the form of an elongate glass rod having first and second parallel polygonal end faces (a,b) which are parallel to the long axis of the rod, the rod having a uniform polygonal cross section along its length. The spatial light modulator () is optically coupled to the second end face (b) of the light guide () and the focussing means () is arranged to receive light reflected back through the rod from the spatial light modulator (), whereby to form multiple images of said spatial light modulator in an image plane ().

Image replication system having focusing means to receive reflected light through lightguide from spatial light modulator

A photosensitive areasuch as a photolithographic sheet, in an images plane is notionally subdivided in both dimensions to form contiguous (tiled) sub-areas. Variable illumination meansprovides a selected pixellated light pattern, which is directedto fill a selected one of the sub-areas so that pixels of said pattern are, at least 15 microns across at the sub-area, and control means are responsive to an input signal representative of an image conjointly to control the production and direction of the pixellated patterns so that an entire image is produced over all of the said sub-areas. As shown, the variable illumination means comprises a light sourcewith digital micro-mirror array deflector deviceand the sub-area is selected by lens arraywith a shutterand polariser array10. The latter may be replaced by a two-axis steering mirror and lens array. An analogue micro-mirror array, optionally with, a kaleidoscope, may be used in the illumination means, with (a) collimating optics and lens array; or (b) a focussing macrolens, for sub-area selection.

Printing by active tiling

A spatial light modulator imaging system comprises an electrically addressed spatial light modulator (EASLM) whose optical image output is projected onto different areas of an optically addressed spatial light modulator (OASLM,) in a sequence. The OASLM carries electrodes which allow separate areas to be selectively addressed by application of a voltage whilst receiving light from the EASLM. The combined output from all areas of the OASLM forms a visible image to an observer (). When illuminated by coherent light the OASLM may produce a holographic image, otherwise incoherent light is used to provide a two dimensional image. The OASLM in one example contains a layer of nematic liquid crystal material between two cell walls both treated with an alignment layer providing low tilt surface alignment that is parallel in opposite direction; the product of layer thickness d and material birefringence &#x394;n approximately equals one quarter of the wavelength &#x3bb; of read light (). Other types of nematic devices may also be used, with cell parameters arranged to give enhanced diffraction efficiency.

Spatial light modulator imaging systems

A device for forming an image on a screen is described that comprises a coherent illumination means, an electrically addressed spatial light modulator means located in the path of light from the coherent illumination means, means for producing computer generated hologram images for display on the electrically addressed spatial light modulator means, and optics to direct light diffracted by the electrically addressed spatial light modulator means to the screen. The device is arranged so that a computer generated image or images displayed by the electrically addressed spatial light modulator means result in a two dimensional image being formed at the screen.

Image projection device and method

A relief structure alignment layer comprising a relief structure surface incorporating at least one indentation, the at least one indentation having an internal surface extending from the relief structure surface, wherein the relief structure alignment layer has a surface memory alignment layer arranged to impart a preferred liquid crystal director alignment to a liquid-crystal material in contact therewith as well as methods for configuring a liquid crystal material within a cell having a relief structure alignment layer by applying at least one of an electric field and a magnetic field and phoretic displays comprising at least on relief structure alignment layer.

Phoretic cell

A phoretic display having a liquid crystal suspension medium and a relief structure alignment layer comprising a relief structure surface incorporating a plurality of indentations. The relief structure alignment layer is adapted to generate a preferred alignment of the liquid crystal suspension medium within the display by creating defects within the alignment of the liquid crystal director at the base of each indentation. The relief structure alignment layer provides a substantially planar liquid crystal director alignment in the vicinity of the internal surface of each indentation and a substantially homeotropic liquid crystal director alignment in the vicinity of the relief structure surface and in the bulk of the liquid crystal material.

Phoretic display

A phoretic display device comprising a plurality of electrophoretic or magnetophoretic cells, each having a phoretic particle dispersed within a suspension medium comprising a liquid crystal material. The phoretic cell is adapted to induce defects, sometimes known as disclinations, in the alignment of the liquid crystal material within the cell which act to exert a retentive force on the phoretic particle when within the region of influence of the defects. The configuration of the display introduces a threshold level in the electric or magnetic field required to move the phoretic particle between defects within the cell. Accordingly, the non-linear electro-optic or magneto-optic behaviour of the display facilitates matrix addressing of the cells therein. The display may comprise a plurality of prolate spheroid phoretic cells arranged in an encapsulant, the major (long) axis of each cell arranged substantially perpendicular to the plane of the display.

Phoretic display device with liquid crystalline suspension medium, and manufacturing method

The present invention relates, in one aspect to an image replication system comprising a light guide (), a light source () arranged to direct emitted light into the first end () of a light guide (), a reflective spatial light modulator () and focussing means (). In a preferred embodiment, the light guide () is in the form of an elongate glass rod having first and second parallel polygonal end faces () which are parallel to the long axis of the rod, the rod having a uniform polygonal cross section along its length. The spatial light modulator () is optically coupled to the second end face () of the light guide () and the focussing means () is arranged to receive light reflected back through the rod from the spatial light modulator (), whereby to form multiple images of said spatial light modulator in an image plane ().

A photosensitive area, such as a photolithographic sheet, in an images plane is notionally subdivided in both dimensions to form contiguous (tiled) sub-areas. Variable illumination meansprovides a selected pixellated light pattern, which is directedto fill a selected one of the sub-areas so that pixels of said pattern are, at least 15 microns across at the sub-area, and control means are responsive to an input signal representative of an image conjointly to control the production and direction of the pixellated patterns so that an entire image is produced over all of the said sub-areas. As shown, the variable illumination means comprises a light sourcewith digital micro-mirror array deflector device, and the sub-area is selected by lens arraywith a shutterand polariser array. The latter may be replaced by a two-axis steering mirror and lens array. An analogue micro-mirror array, optionally with, a kaleidoscope, may be used in the illumination means, with (a) collimating optics and lens array; or (b) a focussing macro-lens, for sub-area selection.

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Malvern, United Kingdom

Richard Jonathan Miller