Nemoptic

France Brevets

Stéphane Joly

Philippe Martinot-Lagarde

Jean-Denis Laffitte

Jean Denis Laffitte

Christophe Body

Ivan N Dozov

Daniel Stoenescu

Jacques Angele

Didier Gallaire

François Leblanc

Jean Claude Dubois

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

A method for addressing a bistable nematic matrix LCD having two stable textures without any applied electric field. Pixel addressing is of the passive multiplex type. The method includes selecting the value of the electrical voltage applied between the substrates so that an average value of the voltage, preferably the average quadratic value, since the initial command for image display up to the time immediately preceding switching, has a predetermined value independent of the information to be displayed, which is the same for all the pixels of the image.

Addressing method for a bistable nematic liquid crystal matrix screen with regulated average quadratic voltage

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 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

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

Growing community of inventors

Saint Saturnin, France

Stéphane Joly