Abstract: A method for the control of a liquid crystal display that includes a matrix of pixels arranged in crossed lines and columns. A switching of state of the liquid crystal molecules, is controlled by application of an electrical control signal between two electrodes (50, 52) framing each pixel, generates a flow according to a particular direction (18), characterized in that, to control the switching of at least some of the pixels (P). The method includes applying to at least one neighboring pixel (58), according to the direction of flow, of a pixel (P) whose switching is controlled by the electrical control signal, auxiliary electrical signals whose amplitude is less than the anchorage breaking voltage and whose rising or falling edges are temporally placed in advance or in coincidence with the active falling edge of the electrical control signal, to favor the switching of the said pixel to be controlled (P).

Abstract: The invention relates to a method for controlling a liquid crystal display, comprising a matrix of pixels arranged in crossed lines and columns and in which a switch in the state of the liquid crystal molecules, controlled by application of an electric control signal between two electrodes (50, 52) enclosing each pixel, which brings about a flow in a given direction (18), the pixel addressing being carried out by a line by line addressing either in a single step or in two steps, the first step comprising a collective addressing of at least a part of the screen in a given single texture, followed by a second step of line by line addressing, characterized in comprising, for controlling the switching of at least some of the pixels (P), a step for application to at least one adjacent pixel (58) of auxiliary electric signals wherein, depending on the direction of flow of the pixel (P) the switching of which is to be controlled, the rising or falling fronts of the auxiliary signals are temporally advanced in relati

Abstract: The present invention provides a nematic liquid crystal composition suitable for a bistable nematic liquid crystal display. A bistable nematic liquid crystal display having a wide nematic phase temperature range and operating temperature range can be obtained by using a nematic liquid crystal composition comprising at least 20% by weight of a specific liquid crystal compound (A) having a polar group and 5 to 50% by weight of a specific liquid crystal compound (B) not having a polar group, along with comprising, in the compound (B), at least 3% by weight of a specific liquid crystal compound having a alkenyl group.

Abstract: A nematic liquid crystal composition of the present invention includes at least 20% by weight of one, or two or more compounds selected from compound group A; and 5 to 50% by weight of one, or two or more compounds selected from compound group B, wherein the relative proportions of the above-mentioned compounds used in the nematic liquid crystal composition is determined to simultaneously obtain the specific physical characteristics for the composition, and an anchoring breaking voltage U?/4 is less than or equal to 25 V when the product (?n·d) of the refractive index anisotropy (?n) at 20° C. and the thickness (d) is 140 nm and the liquid crystal composition is confined between two substrates for a bistable nematic liquid crystal display in which at least one of the substrates have a weak zenithal anchoring force.

Abstract: The application relates to a single-polarizer reflective bistable twisted nematic (BTN) liquid crystal display device comprising a liquid crystal layer of thickness d, birefringence ?n and retardation ?nd, said liquid crystal layer being situated between two substrates and between a polarizer and a reflector, said liquid crystal layer in the absence of an applied electric field having two stable uniformly twisted textures, the twists of the two stable textures differing by an angle being equal mainly to 180°, and at least one compensation layer positioned between said polarizer and said reflector, said compensation layer being composed of at least one birefringent film, said birefringent film having an optical anisotropy defined by three characteristic refractive indices nx, ny, nz, along three corresponding axis x, y, z of index ellipsoid, x and y being situated inside the substrates plane, nx and ny being called in plane indices, with nx?ny, x being called slow axis, and z being perpendicular to the substra

Abstract: The present invention relates to a display device comprising a bistable nematic liquid-crystal matrix screen with anchoring breaking, characterized in that it comprises: components (40) capable of switching between an off state and an on state, these components being placed respectively between a drive electrode (47) associated with each pixel and a display state control link (45); and means capable of applying, to the input of each aforementioned component (40), via the state control link (45), input signals comprising at least two phases separated by a controlled time interval, namely a first phase during which the input signal has an amplitude sufficient to permit breaking of the anchoring of the liquid crystal on the associated pixel, then a second phase during which the amplitude of the input signal is controlled in order to select one of the two bistable states of the liquid crystal, the time interval between the two phases being adapted in order to break the anchoring of the liquid crystal on the sa

Abstract: The invention concerns a liquid crystal display device comprising two substrates (10, 20) provided with respective electrodes (12, 22) and located on either side of a layer of liquid crystal molecules (30) and means defining two stable states for the liquid crystal molecules, in the absence of an electric field.

Abstract: The invention relates to a bistable nematic liquid crystal matricial display device wherein the shift to one of the at least two bistable states is carried out by displacing the liquid crystal parallel to the surfaces of the device, characterized by the fact that it comprises a system for addressing various elements of the display device, characterized in that it comprises a system for addressing the various elements of the display device such that it does not simultaneously shift two adjacent elements located in the direction in which the material flows. The invention also relates to a display method. The invention makes it possible to control the grey level by controlling the scan rings of the hydrodynamic flow in order to define the border between two different textures.

Abstract: A device nematic liquid crystal display device has two stable states corresponding to two liquid crystal molecule textures whose torsion differs by 150° to 180° in terms of absolute value. The device includes two polarizers (10, 40), one (10) of which is placed on the observer side, the other (40) being placed on the opposite side of the liquid crystal cell. The orientation of the two polarizers is offset by a value which is equal to the rotatory power of the cell+/??/2, the rotatory power corresponding to the most twisted texture effect.

Abstract: The invention relates to a nematic liquid crystal display having two stable states, without an electric field, obtained by anchoring break, characterized in that it comprises two polarizers (10, 40), one (10) of which is placed on the observer side, the other (40) being placed on the opposite side of the liquid crystal cell whereby the latter is at least partially reflecting in order to define a reflective mode or transflective mode. The orientation of the two polarizers (10, 40) is offset by a value which is equal to the rotatory power of the cell at approximately +/?30°.

Abstract: A method of electrically addressing a matrix screen of bistable nematic liquid crystals with breaking of anchoring is disclosed. Controlled electrical signals are applied respectively to row electrodes and to column electrodes of the screen. A plurality of rows are simultaneously addressed using similar row signals that are offset in time by a duration greater than or equal to the time column voltages that are applied. The row addressing signals have, in a first period, at least one voltage value serving to break the anchoring of all of the pixels in the row. This is followed by a second period that enables the final states of the pixels making up the address row to be determined. The final states are a function of the value of each of the electrical signals applied to the corresponding columns.

Abstract: The present invention relates to a nematic bistable display device, characterized in that it comprises control means (40) for producing, after the anchoring is broken, hybrid textures in which two bistable textures coexist in a controlled proportion within the same pixel, these being separated by 180° volume disclination lines or by 180° reorientation walls on one of the surfaces, and means (40) for the long-term stabilization of the hybrid textures by transformation of the volume lines into surface walls and the immobilization of these walls on the surface.

Abstract: This invention concerns a process for addressing a bistable liquid crystal material screen, characterized in that it comprises at least the step consisting of applying, to the screen column electrodes, an electrical signal whose characteristics are adapted to reduce the mean quadratic voltage of the parasite pixel pulses, in order to reduce the parasitic addressing optical effects.

Abstract: Nematic liquid crystal mixtures with weak zenithal anchoring energy for bistable display devices, comprising at least 40% by weight of compounds with strong molecular polarisability and strong dipole moment.

Abstract: The invention relates to a bistable nematic liquid-crystal device comprising: alignment means, which orient the liquid crystal, means designed to apply electrical signals which allow switching, by breaking the anchoring on at least one of the two substrates, between two distinct textures, and means designed to promote the establishment of that one of the said textures giving the off state in the liquid crystal covering the inter-electrode spaces.

Abstract: A method of making nematic liquid crystal devices where low energy zenith anchoring of the liquid crystal is obtained over confinement plates. A polymer or copolymer is deposited based on PVC onto a substrate. The polymer deposit is stabilized. An azimuth orientation is defined for the deposit to induce controlled azimuth anchoring of the liquid crystal.

Abstract: Method of producing nematic liquid-crystal devices, wherein a low zenithal anchoring energy of the liquid crystal is obtained on at least one of its confinement plates by the steps consisting in: depositing, on a substrate, a polymer or a copolymer or a terpolymer chosen from the polymers or copolymers derived from those of the poly(vinyl chloride-co-vinyl alkyl ether) type or from those of the poly(vinyl chloride-co-vinyl aryl ether) type; stabilizing this polymer coating; and defining an azimuthal orientation of the coating for inducing a controlled azimuthal anchoring of the liquid crystal.

Abstract: The present invention relates to novel polyimides derived from 6FDA and from 3,3-dihydroxy-4,4?-diaminobiphenyl and novel polyimides derived from PMDA and from Bis-AP-AF, having alkyl, arylalkyl, heteroarylalkyl, (cycloalkyl)alkyl, fluoroalkyl or siloxane side groups. The present invention also relates to a method of producing nematic liquid-crystal devices, which comprises the steps consisting in: depositing one of the polyimides according to the invention on a substrate; annealing the polyimide in one or more steps; and defining an azimuthal orientation of the polyimide coating.

Abstract: The present invention provides an electro-optical device, characterized in that it comprises two plane optical substrates (100) each having at least one optical waveguide (110), and a nematic liquid crystal (200) inserted between them, in which the liquid crystal (200) is split into two separate active zones (210, 220) serving to control coupling/decoupling of a respective one of the TE and TM polarizations of a light signal injected into the waveguides (110).

Abstract: The present invention relates to a liquid crystal display device comprising a liquid crystal material sandwiched between two confinement plates (1, 2), the device being characterized by the fact that at least one of the plates (2) is provided with treatment which defines degenerate or nearly degenerate azimuth anchoring without azimuth orientation memory.