(US5384067-A)      A light modulating device comprises liq. crystalline light modulating material comprising phase-sepd. polydomains of polymer network dispersed in liq. crystal, the liq. crystal being a chiral nematic having positive dielectric anisotropy and the polymer being present in amt. less than 10 wt.% based on the combined wt. of liq. crystal and polymer, in which the proportion of material in the first optical state and the remainder of material is in the second optical state.    The cell wall structure is treated to align the liq. crystal mols. by application of a coating on the cell wall structure, and a means to establish an electrical field through the material, which can provide an AC pulse of sufficient voltage and duration to change the proportion of the material in the first optical state, in which the intensity of light reflected may be selectively adjusted.    ADVANTAGE -   The material exhibits a unique combination of properties that afford significant advantages over preceding technology.    (JP7507083-W)      Light modulating cell comprises light modulating material of liq. crystal (16) and polymer (15). The liq. crystal is a chiral nematic liq. crystal having positive dielectric anisotropy and including chiral material in an amt. effective to form focal conic and twisted planar textures (30). The polymer is distributed in phase separated domains (15) in an amt. that stabilises the focal conic and twisted planar textures in the absence of a field and permits the liq. crystal to change textures when a field is applied.    The cell is switched between a stable, colour reflecting stage that reflects a max. reference intensity and a stable light scattering state exhibiting min. reference intensity of reflection by applying a voltage pulse. By applying voltage pulses of varying magnitude, a continuum of stable states having colour reflectivity of an intensity between the max. and min. are obtd.    USE/ADVANTAGE -   Light modulating cell is esp. a bistable light shutter which can be switched between a stable, optically clear state and a stable light scattering state by applying or removing an electric field. Material can operate in a light scattering mode in a field-OFF condition and clear in a field-ON condition or vice versa. The material exhibits minimal haze at all viewing angles in the clear state without any need for light-reducing polarisers. It does not require an active matrix to make a high-definition panel screen.    (US5691795-A)      A light-modulating cell comprises a liquid crystalline light-modulating material of liquid crystal (LC) and phase-separated domains of polymer, which form a cell wall structure. The LC is a chiral nematic LC having positive dielectric anisotropy, and including an amount of chiral material effective for forming a focal conic texture with a pitch length such that it can reflect light outside the visible spectrum. The cell wall structure and the LC cooperate to form a stable focal conic texture in the absence of a field, and allow the LC to change textures when a field is applied. The phase-separated domains are formed in the presence of a field sufficient to cause homeotropic alignment of the LC such that part of it in the vicinity of the domains has a preferential homeotropic alignment in the absence of a field. The resulting material has a light-scattering focal conic texture in the absence of a field and an optically clear homeotropic alignment in a field-ON condition.    Also claimed is a light-modulating device.    USE -   In electro-optical devices, e.g. large-area displays, projection displays, high-definition television and switchable coatings for windows.    ADVANTAGE -   The material may be light scattering in the field-OFF state and clear in the field-ON state, or vice versa. It shows minimal haze at all viewing angles when clear. It may exist in multiple, optically different states. The optical state can be changed to a new, stable state according to the magnitude and shape of an applied electric field pulse, and a stable "gray scale" can be provided. A low field pulse provides a white coloured scattering state. The material can be driven to a light-reflecting state of any desired colour. Intermediate stable states between light-reflecting and light-scattering can be produced. Applying mechanical stress can also drive the material from light-scattering to light-reflecting. An active matrix is not required to make a high-definition, flat-panel screen. Polarisers, which limit the brightness of the displays, are not required and colours can be produced without the use of colour filters, which can also reduce brightness.    (US5695682-A)      Light modulating cell comprises light modulating material of liq. crystal (16) and polymer (15). The liq. crystal is a chiral nematic liq. crystal having positive dielectric anisotropy and including chiral material in an amt. effective to form focal conic and twisted planar textures (30). The polymer is distributed in phase separated domains (15) in an amt. that stabilises the focal conic and twisted planar textures in the absence of a field and permits the liq. crystal to change textures when a field is applied.    The cell is switched between a stable, colour reflecting stage that reflects a max. reference intensity and a stable light scattering state exhibiting min. reference intensity of reflection by applying a voltage pulse. By applying voltage pulses of varying magnitude, a continuum of stable states having colour reflectivity of an intensity between the max. and min. are obtd.    USE/ADVANTAGE -   Light modulating cell is esp. a bistable light shutter which can be switched between a stable, optically clear state and a stable light scattering state by applying or removing an electric field. Material can operate in a light scattering mode in a field-OFF condition and clear in a field-ON condition or vice versa. The material exhibits minimal haze at all viewing angles in the clear state without any need for light-reducing polarisers. It does not require an active matrix to make a high-definition panel screen.    (EP641372-B1)      Light modulating cell comprises light modulating material of liq. crystal (16) and polymer (15). The liq. crystal is a chiral nematic liq. crystal having positive dielectric anisotropy and including chiral material in an amt. effective to form focal conic and twisted planar textures (30). The polymer is distributed in phase separated domains (15) in an amt. that stabilises the focal conic and twisted planar textures in the absence of a field and permits the liq. crystal to change textures when a field is applied.    The cell is switched between a stable, colour reflecting stage that reflects a max. reference intensity and a stable light scattering state exhibiting min. reference intensity of reflection by applying a voltage pulse. By applying voltage pulses of varying magnitude, a continuum of stable states having colour reflectivity of an intensity between the max. and min. are obtd.    USE/ADVANTAGE -   Light modulating cell is esp. a bistable light shutter which can be switched between a stable, optically clear state and a stable light scattering state by applying or removing an electric field. Material can operate in a light scattering mode in a field-OFF condition and clear in a field-ON condition or vice versa. The material exhibits minimal haze at all viewing angles in the clear state without any need for light-reducing polarisers. It does not require an active matrix to make a high-definition panel screen.