73 results about "Chiral nematic liquid crystal" patented technology

Provided are multilayer laminates having one or more layers comprising twisted nematic liquid crystals and one or more layers of a polymeric sheet. The twisted nematic liquid crystal layers reflect infrared radiation. Thus, the multilayer laminates are useful to reduce the transmission of infrared energy. For example, in some embodiments the multilayer laminates are useful as windows to reduce energy consumption necessary to cool the interior of a structure such as an automobile or building. Preferably, the multilayer laminates retain one or more of the beneficial properties of safety glass. The multilayer laminates may include additional layers such as infrared absorbing layers, half wave plates, and the like, to minimize the transmission of infrared energy. The multilayer laminates may also include further additional layers such as polymeric films, polymeric sheets, rigid sheets, and the like.

A display sheet comprising a substrate carrying layers of material; including a polymer-dispersed chiral-nematic liquid-crystal layer having a first high reflection state within the visible light spectrum and a second less-reflective state in said spectrum, said states being changeable by an electric field, which states can be maintained in the absence of an electric field; a first transparent conductor disposed over said polymer-dispersed chiral-nematic liquid-crystal layer; and a second conductor, wherein said imaging layer is substantially a monolayer of said domains comprises a mixture of at least two differently reflecting liquid crystal materials, in which the λ maximums of the two materials are separated by 100 to 250 nm.

The present invention relates to a bistable polymer dispersed liquid crystal display comprising a support, at least one patterned first conductor layer having thereon at least one dried imaging layer comprising a substantial monolayer of isolated domains of liquid crystal material dispersed in a continuous polymer matrix, wherein said dried imaging layer further comprises at least one absorber colorant, and wherein said isolated domains have a size distribution such that the coefficient of variation (cv) is less than 0.35.

A reflective type liquid crystal display which has a liquid crystal composition exhibiting a cholesteric phase in a room temperature and a columnar structure between substrates with ITO electrodes thereon. The liquid crystal composition is a chiral nematic liquid crystal composition which is produced by adding a chiral agent at a ratio within a range from 10 wt % to 45 wt % to nematic liquid crystal which contains a nematic liquid crystal component with a polar group at not less than 25 wt % and of which transition temperature to isotropic phase is within a range from 70° C. to 150° C. The anisotropy of refractive index of the liquid crystal composition is 0.10 to 0.22, and the anisotropy of dielectric constant is 5 to 30.

On substrates 2a, 2b of a chiral nematic liquid crystal optical element 1, transparent electrodes 3a, 3b and electrical insulation layers 4a, 4b are formed, and further, resin layers 5a, 5b hating a pencil hardness of “B” or less are formed on the electrical insulation layers by a spin coating method so as to be in contact with a liquid crystal layer 7. When the surface hardness of the resin layers is to be measured, a glass substrate on which a resin layer is formed by screen-printing is prepared as a test piece, and the test piece is fitted to a pencil-scratching tester. The surface hardness is measured by scratching the test piece with two kinds of testing pencil selected from testing pencils having 17 grades of density.

The present invention provides a laminated retardation optical element that never lowers contrast and thus never degrades display performance even when placed between a liquid crystal cell and a λ / 4 retardation film. In a liquid crystal display 90, a laminated retardation optical element 10 is placed between a polarizer 102A on the incident side and a liquid crystal cell 104, and a λ / 4 retardation film 102C is placed between a polarizer 102B on the emergent side and the liquid crystal cell 104. The laminated retardation optical element 10 comprises: a λ / 4 retardation layer 14 having the function of bringing, to light that passes through this retardation layer, a phase difference corresponding to a quarter of the wavelength of the light; and a C plate-type retardation layer 16 that acts as a negative C plate. The λ / 4 retardation layer 14 and the C plate-type retardation layer 16 are laminated to a transparent substrate 12 in the order mentioned, and are optically bonded to each other. The λ / 4 retardation layer 14 comprises as its main component a horizontally-aligned, cross-linked nematic liquid crystal, while the C plate-type retardation layer 16 comprises as its main component a cross-linked chiral nematic liquid crystal (a cross-linked nematic liquid crystal and a cross-linked chiral agent) or cross-linked discotic liquid crystal.

A liquid crystal display apparatus which has: a liquid crystal display which has chiral nematic liquid crystal between a pair of substrates with electrodes thereon and which makes a display by use of selective reflection of the liquid crystal; and a driving circuit for driving the liquid crystal by applying voltages to the electrodes. When an electric field of a specified strength is applied to the chiral nematic liquid crystal, the liquid crystal changes the direction of the helical axis without untwisting. By using this characteristic, the direction of the helical axis of the liquid crystal is changed by changing the direction of the electric field applied thereto, and thereby, the liquid crystal is set to a planar state or a focal-conic state. In this way, writing on the liquid crystal is carried out.

A normally white supertwist nematic liquid crystal display of reflective type is provided. This display comprises a reflector, a layer of chiral nematic liquid crystal having a front aligning surface facing a light source and a rear aligning surface facing the reflector, and a front polarizer. The nematic liquid crystal has an optical retardation (Δnd) of the layer and a distribution of directors, wherein the chiral nematic liquid crystal has a twist angle (Φ) between an alignment direction of the director at the front aligning surface and an alignment direction of the director at the rear aligning surface. The front polarizer is disposed between the layer of chiral nematic liquid crystal and the light source. The front polarizer has a transmission axis forming an angle (α) with the alignment direction of the director at the front aligning surface of the chiral nematic liquid crystal layer. The optical retardation (Δnd) and the angle (α) are defined by the following formulas:α((Φ)=sign(Φ)·(47.0−0.4936|Φ|+2.6786×10−3·Φ2)±5, deg, andΔnd(Φ)=−11.674+0.1915·|Φ|−9.8393×10−4·Φ21.6667×10−6·|Φ|3±0.05, μm.

A chiral nematic liquid crystal composition has minimal temperature dependency of the natural pitch and temperature dependency of the wavelength selective reflection and low temperature storage stability thereof is excellent. A chiral nematic liquid crystal composition with a broad liquid crystal temperature range is used in a bistable liquid crystal display element, and a bistable liquid crystal display element comprising the liquid crystal composition. The chiral nematic liquid crystal composition comprises optically active compounds represented by general formula (I-a) and general formula (II-a) wherein the general formula (II-a) has the same helical twisting direction as the general formula (I-a), and shows a positive temperature dependency for the natural pitch, and a HTP value of at least 3.

A display sheet comprising a substrate carrying layers of material; including a polymer-dispersed chiral-nematic liquid-crystal layer having a first high reflection state within the visible light spectrum and a second less-reflective state in said spectrum, said states being changeable by an electric field, which states can be maintained in the absence of an electric field; a first transparent conductor disposed over said polymer-dispersed chiral-nematic liquid-crystal layer; and a second conductor, wherein said imaging layer is substantially a monolayer of said domains comprises a mixture of at least two differently reflecting liquid crystal materials, in which the λ maximums of the two materials are separated by 100 to 250 nm.

This invention generally relates to a liquid crystal device, and more particularly to such a device in the form of a liquid crystal cell such as for a display device, and further relates to a display device having the liquid crystal device, an optical waveguide device comprising the liquid crystal device, a Variable Optical Attenuator comprising the liquid crystal device, an optical switch comprising the liquid crystal device, a method of controlling transmission of polarised light, and to a further liquid crystal device. A liquid crystal device for controlling transmission of polarised light, comprising: chiral nematic liquid crystal having a helical arrangement of liquid crystal molecules in the absence of an electric field; and at least two electrodes for applying an electric field having a component normal to the helical axis of the chiral nematic liquid crystal, wherein the chiral nematic liquid crystal has negative dielectric anisotropy.

Reflective chiral nematic liquid crystal material is disposed between a first set of electrodes and a second set of electrodes arranged on opposed sides of the material to define a collection of pixels. Fast updating dynamic drive scheme is implemented by selectively applying an electric field via the electrodes through the pixels in four phases of energization: preparation, selection, evolution, and non-select. Each phase is made up of a series of voltages having varying amplitudes. The voltage waveform is for each phase controlled based on the selection phase to achieve image uniformity. For example, the evolution voltages that are established across adjacent pixels having the same final state have initial amplitudes that are equal for both pixels to increase image uniformity.