Abstract: An electrically switchable optical modulator for modulating an optical wavefront transmitted therethrough, comprising a birefringent first optical element and a birefringent second optical element each having respective ordinary and extraordinary refractive indices. A birefringent liquid crystal material is sandwiched between the first and second optical elements. The extraordinary refractive index of the liquid crystal material is electrically switchable between: a first state in which it has a first value; and, a second state in which it has a second value different from the first value. One or both of the first value and the second value is un-matched to the extraordinary refractive index of the first optical element in respect of light polarised in a first direction of linear polarisation, and is un-matched to the extraordinary refractive index of the second optical element in respect of light polarised in a second direction of linear polarisation orthogonal to the first direction.

Abstract: An electrically switchable optical modulator for modulating an optical wavefront transmitted therethrough, comprising a birefringent first optical element and a birefringent second optical element each having respective ordinary and extraordinary refractive indices. A birefringent liquid crystal material is sandwiched between the first and second optical elements. The extraordinary refractive index of the liquid crystal material is electrically switchable between: a first state in which it has a first value; and, a second state in which it has a second value different from the first value. One or both of the first value and the second value is un-matched to the extraordinary refractive index of the first optical element in respect of light polarised in a first direction of linear polarisation, and is un-matched to the extraordinary refractive index of the second optical element in respect of light polarised in a second direction of linear polarisation orthogonal to the first direction.

Abstract: Disclosed is a dynamically switchable contact lens, operable to switch between first and second focal states, each focal state having a different optical property, the lens comprising: a power source; a controller, operable to control the operation of the lens; a transceiver operable to communicate with a second lens and/or an external controller; wherein the controller is operable to pair the lens with the second lens by means of the external controller.

Abstract: A liquid crystal device (100) for focusing visible light, the liquid crystal device (100) comprising a plurality of curved substrates (101,102) arranged to form one or more curved cavities (104) therebetween, each substrate being configured to provide a focal power, wherein the one or more curved cavities contain liquid crystal and form one or more liquid crystal elements. Each of the one or more liquid crystal elements are configured to provide a focal power, the focal power of each of the liquid crystal elements being dependent on the curvature of the respective cavity and a voltage applied across the liquid crystal contained within the respective cavity. The substrates (101,102) in combination with the one or more liquid crystal elements are arranged to provide a first focal power in a substantial absence of an applied voltage and a second focal power in response to an applied voltage.

Abstract: A liquid crystal device (100) for focusing visible light, the liquid crystal device (100) comprising a plurality of curved substrates (101,102) arranged to form one or more curved cavities (104) therebetween, each substrate being configured to provide a focal power, wherein the one or more curved cavities contain liquid crystal and form one or more liquid crystal elements. Each of the one or more liquid crystal elements are configured to provide a focal power, the focal power of each of the liquid crystal elements being dependent on the curvature of the respective cavity and a voltage applied across the liquid crystal contained within the respective cavity. The substrates (101,102) in combination with the one or more liquid crystal elements are arranged to provide a first focal power in a substantial absence of an applied voltage and a second focal power in response to an applied voltage.

Abstract: The invention relates to a method of patterning a layer formed from a fixable material such as photopolymer on a surface in a desired pattern. The method involves coating selected areas of the substrate with an adhesion promoter and subsequently coating the fixable material. The fixable material is then fixed, for instance by curing by exposure to UV radiation. The adhesion promoter is adapted to have a surface energy which is designed to adhere to the substrate or selected areas thereof and also to the fixed material such that fixed material may be easily removed from areas of the substrate not coated with adhesion promoter but retained in areas where the adhesion promoter has bonded to the substrate.

Abstract: A display system 10 for displaying information at a point of product display in a retail outlet comprising a communicator 12 for transmitting display information to a remote display module 18, the display module 18 being adapted in a first, low power mode to display information and in a second, higher power mode periodically, in a predetermined manner, to communicate with the communicator 12, the system 10 preferably being configured to enable determination of the accuracy and automated correction of the synchronization of a periodic communication between the communicator 12 and the display module 18 while the display module 18 continues to switch between first and second modes of operation enabling a low overall consumption of power by the display module 18 and more preferably wherein the display module 18 is adapted to switch between first and second power modes between receipt of a synchronization signal and a display information signal from the communicator 12.

Abstract: The invention relates to a method of patterning a layer formed from a fixable material such as photopolymer on a surface in a desired pattern. The method involves coating selected areas of the substrate with an adhesion promoter and subsequently coating the fixable material. The fixable material is then fixed, for instance by curing by exposure to UV radiation. The adhesion promoter is adapted to have a surface energy which is designed to adhere to the substrate or selected areas thereof and also to the fixed material such that fixed material may be easily removed from areas of the substrate not coated with adhesion promoter but retained in areas where the adhesion promoter has bonded to the substrate.

Abstract: This invention relates to a liquid crystal device wherein the surface profile of a surface alignment grating stabilizes at least one stable state. The invention involves the introduction or breaks (34, 36, 38) or discontinuities into the grating (10) to divide the grating into a plurality of groove segments. The breaks are discontinuities in the grating in the groove direction, the grating having substantially the same groove direction on each side of the break. The introduction of breaks prevent free movement of defects along the groove of the grating and therefore help to stabilize the desired liquid crystal configuration, either a Defect state or a Continuous state. Suitable breaks involve gaps (34) in the groove ridges (30), necks (36) between the groove ridges (30) and slips or relative displacement (38) of the grating.

Abstract: A display system 10 for displaying information at a point of product display in a retail outlet comprising a communicator 12 for transmitting display information to a remote display module 18, the display module 18 being adapted in a first, low power mode to display information and in a second, higher power mode periodically, in a predetermined manner, to communicate with the communicator 12, the system 10 preferably being configured to enable determination of the accuracy and automated correction of the synchronisation of a periodic communication between the communicator 12 and the display module 18 while the display module 18 continues to switch between first and second modes of operation enabling a low overall consumption of power by the display module 18 and more preferably wherein the display module 18 is adapted to switch between first and second power modes between receipt of a synchronisation signal and a display information signal from the communicator 12.

Abstract: The invention is directed to liquid crystal compositions for use in bistable liquid crystal devices and to bistable liquid crystal devices containing said liquid crystal compositions. The liquid crystal composition comprises a component (?) said component (?) containing one or more compounds having a phenyl ring of formula A Whereby XA is F, CI, SF5, NCS or a C1 to C8 alkanyl, alkenyl or alkoxy radical substituted with at least one F atom; and LA is H or F.

Abstract: The invention is directed to the use of a liquid crystal composition in a bistable liquid crystal device and especially in a single polariser reflective or transflective zenithal bistable nematic liquid crystal device as well as a bistable liquid crystal device comprising the liquid crystal composition.

Abstract: The invention is directed to the use of a liquid crystal composition in a bistable liquid crystal device and especially in a zenithal bistable nematic liquid crystal device, a nematic liquid crystal medium, and a bistable liquid crystal device comprising the liquid crystal composition whereby said liquid crystal composition comprises at least 30 weight % (based on the total weight of the composition) of a component (?) containing one or more compounds having a dielectric anisotropy ?? of at least 25, whereby at least 25 weight % (based on the total weight of the composition) of said compounds have a dielectric anisotropy ?? of at least 40; and at least 5 weight % of a component (?).

Abstract: A bistable nematic liquid crystal device cell is provided with a surface alignment grating on at least one cell wall and a surface treatment on the other wall. Such treatment may be a homeotropic alignment or a planar alignment with or without an alignment direction, and zero or a non zero pretilt. The surface profile on the monograting is asymmetric with its groove height to width selected to give approximately equal energy within the nematic material in its two allowed alignment arrangements. The monograting may be formed by a photolithographic process or by embossing of a plastics material. The cell is switched by dc pulses coupling to a flexoelectric coefficient in the material, or by use of a two frequency addressing scheme and a suitable two frequency material. Polarisers either side of the cell distinguish between the two switched states. The cell walls may be rigid or flexible, and are coated with electrode structures, e.g.

Abstract: The invention is directed to the use of a fast switching liquid crystal composition said composition comprising at least 30 weight % of a component (?) containing one or more compounds having a dielectric anisotropy ?? of at least 25, whereby at least 25 weight % of said compounds have a dielectric anisotropy ?? of at least 40; and at least 5 weight % of a component (?) containing one or more compounds having a ratio of ?1/TNIK of 0.51 mPa·s/K or less, a clearing point TNI of at least 100° C. and a rotational viscosity ?1 of not more than 190 mPa·s (wherein ?1 is the rotational viscosity at 20° C. in mPa·s and TNIK is the clearing point in degrees Kelvin); in a bistable liquid crystal device and especially in a zenithal bistable nematic liquid crystal device, a nematic liquid crystal medium, and a bistable liquid crystal device comprising said fast switching liquid crystal composition.

Abstract: In a liquid crystal device a substrate (1) 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 (3) 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).

Abstract: Liquid crystal devices are formed by a layer of a liquid crystal material enclosed between two cell walls, both carrying electrode structures, and one or both walls treated to align molecules of the liquid crystal material. Most alignment treatment give alignment and surface pretilt with a strong azimuthal and zenithal anchoring energy to contacting liquid crystal molecules. The invention reduces at least one of the azimuthal zenithal or translational anchoring energy to improve switching characteristics and optical performance by allowing movement of liquid crystal molecules at or close to the cell wall. The reduction of anchoring energy may be achieved by an oligomer or short chain polymer which is either spread on the surface or added to the liquid crystal material. The size of oligomer or short chain polymer is low enough that it does not appreciably phase separate from the liquid crystal material.

Abstract: A bistable nematic liquid crystal device cell is provided with a surface alignment grating on at least one cell wall and a surface treatment on the other wall. Such treatment may be a homeotropic alignment or a planar alignment with or without an alignment direction, and zero or a non zero pretilt. The surface profile on the monograting is asymmetric with its groove height to width selected to give approximately equal energy within the nematic material in its two allowed alignment arrangements. The monograting may be formed by a photolithographic process or by embossing of a plastics material. The cell is switched by dc pulses coupling to a flexoelectric coefficient in the material, or by use of a two frequency addressing scheme and a suitable two frequency material. Polarisers either side of the cell distinguish between the two switched states. The cell walls may be rigid or flexible, and are coated with electrode structures, e.g.

Abstract: A bistable nematic liquid crystal device cell is provided with a surface alignment grating on at least one cell wall and a surface treatment on the other wall. Such treatment may be a homeotropic alignment or a planar alignment with or without an alignment direction, and zero or a non zero pretilt. The surface profile on the monograting is asymmetric with its groove height to width selected to give approximately equal energy within the nematic material in its two allowed alignment arrangements. The monograting may be formed by a photolithographic process or by embossing of a plastics material. The cell is switched by dc pulses coupling to a flexoelectric coefficient in the material, or by use of a two frequency addressing scheme and a suitable two frequency material. Polarisers either side of the cell distinguish between the two switched states. The cell walls may be rigid or flexible, and any coated with electrode structures, e.g.

Abstract: In a liquid crystal device a substrate (1) 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 (3) 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).