Nemoptic

Centre National De La Recherche Scientifique

Nemoptic, S.a.

France Brevets

Philippe Martinot-Lagarde

Ivan N Dozov

Daniel Stoenescu

Jacques Angele

Georges E Durand

Stéphane Joly

Alain Boissier

Romain Vercelletto

Didier Gallaire

François Leblanc

Eric Polossat

Jean Denis Laffitte

Jean-Claude Dubois

Jean-Denis Laffitte

Michele Giocondo

Sandrine Lamarque-Forget

Christophe Body

Bertrand Pecout

Jean-Francois Legay

Olivier Duhem

Sandrine Forget

Olivier Ou Ramdane

Philippe Auroy

Eric Raspaud

Stephane Joly

Ioannis Lelidis

Jean Claude Dubois

Maurizio Nobili

Mohamed Monkade

Ricardo Barberi

Marguerite Boix

Julien Roux

Claude Germain

Ivan Dozov

Jean-Denis Laffite

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 () framing each pixel, generates a flow according to a particular direction (), 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 (), 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).

Liquid crystal display device and control method for a bistable nematic liquid crystal display having two stable textures comprising a uniform or slightly twisted state

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 () enclosing each pixel, which brings about a flow in a given direction (), 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 () 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 relation to or simultaneous with the active falling front of the electric control signal with a time offset of between 0 and several tens of microseconds at ambient temperature, such as to promote the switching of said pixel (P) for control, said auxiliary electric signals being applied in the second step when the addressing is in two steps. The invention further relates to a display.

Liquid crystal display device with improved switching means

The present invention relates to a display device comprising a bistable nematic liquid-crystal matrix screen with anchoring breaking, characterized in that it comprises:

Bistable nematic liquid crystal display device and method for controlling such a device

The present invention provides a display device comprising a bistable nematic liquid crystal matrix screen with breaking of anchoring, the device being characterized in that it includes addressing means suitable for generating and applying control signals to each pixel of the matrix screen, the control signals having sloping rising edges presenting a gradient lying in the range 0.5 V/&#x3bc;s to 0.0001 V/&#x3bc;s.

Bistable nematic liquid crystal display method and device

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.

Advanced method and device with a bistable nematic liquid crystal display

A method of using a liquid crystal composition in a bistable liquid crystal device having a weak zenithal anchoring comprising at least 40% by weight of compounds with strong molecular polarisability and strong dipole moment.

Nematic liquid crystal mixtures for use in bistable display devices

The present invention relates to a nematic bistable display device, characterized in that it comprises control means () 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&#xb0; volume disclination lines or by 180&#xb0; reorientation walls on one of the surfaces, and means () 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.

Nematic liquid crystal bistable display device with grey level

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.

Nematic liquid crystal mixtures for bistable display device

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.

Bistable nematic liquid crystal display device with improved optical mask, having textures differing by about 180&#xb0; twist, and off state in the liquid crystal covering the inter-electrode spaces

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.

Method for producing a liquid crystal device with low zenithal anchoring energy, and resulting device

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

Liquid crystal-based electro-optical device forming, in particular, a switch

The present invention relates to a reflective liquid crystal display device comprising a liquid crystal material ( ) contained between two parallel substrates ( ) provided with aligning means on the electrodes to orient the liquid crystal and enable at least two alternative distinct textures that are stable or metastable in the absence of a field to be obtained, means for applying electrical signals to the liquid crystal to perform switching by enabling anchoring on at least one of the two substrates to be broken, a polarizer ( ) associated with the front face of the device and oriented at an angle lying in the range 15&deg; to 75&deg; relative to the director of the liquid crystal on the front face of the device, and a specular or diffusing reflective element ( ) placed at the rear face of the liquid crystal.

Reflective bistable display device incorporating a liquid crystal material

The invention concerns a bistable device comprising a liquid crystal material, aligning means, which orient the liquid crystal to provide two stable or metastable textures, means for applying electric signals enabling to switch between the two textures, a polarizer ( ) associated with the front surface of the device, placed inside or outside same, a reflective, specular or diffusing element, placed on the rear surface of the liquid crystal, inside or outside the device, allowing light to pass through the device twice and to return towards the observer or towards additional optical elements, and a compensator ( ), placed between the polarizer and the reflective element, with an optical retardation d &Dgr;n close to &lgr; /4.

Bistable device for reflection display with inverse contrast

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

Liquid crystal device comprising anchoring means on at least one confinement plate providing a degenerated orientation

A display device including two parallel transparent plates (,) having transparent electrodes on the inner surfaces thereof and containing a liquid crystal material (,). The device includes means defining a monostable anchoring for each plate (,), means (,) controllable to break at least one of the anchorings, and means for thereafter inducing volume bistability.

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Marcoussis, France

Philippe Martinot-Lagarde