Patent ID: 11927863
Assignee: COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 15:
16. A device for modulating a phase of a light beam, comprising:
a matrix of elementary cells, called pixels, coupled to a circuit for addressing said pixels, each elementary cell comprising a liquid crystal layer (CL) and, on either side of said liquid crystal layer, at least one first electrode (ELP) called pixel electrode controlled by at least one control transistor coupled to said addressing circuit, and a second electrode (EL2) that is transparent and common to all the cells,
the liquid crystal being composed of molecules having a natural orientation of rest in a plane of said device and in a so-called horizontal direction of alignment (Xa) oriented along a so-called horizontal row of pixels, and in the absence of voltage between the at least one pixel electrode and the second electrode, and another orientation outside of said plane of said device in the presence of voltage between the at least one pixel electrode and the second electrode, called activation voltage (Vact), said activation voltage being applied in a phase of activation of the liquid crystal molecules,
the device further comprising a set of so-called lateral electrodes extending in a so-called vertical direction (Y) at right angles to said alignment direction (Xa), disposed on a same plane as the pixel electrode and configured to apply, for each pixel and via at least two lateral electrodes, a so-called acceleration voltage (Vacc) generating a lateral electrical field (Era) substantially parallel to said alignment direction, in a vector allowing an accelerated return of the liquid crystal molecules to their orientation of rest, said acceleration voltage being configured to be applied in a phase called accelerated relaxation phase, when the activation voltage is no longer applied,
wherein, for each pixel, the pixel electrodes and the lateral electrodes are combined and called elementary electrodes, said elementary electrodes taking the form of a strip of substantially identical dimensions and extending in the vertical direction, said elementary electrodes being divided up into a first group and a second group of one strip in every two,
said elementary electrodes being configured to apply, in combination with the second electrode, a same activation voltage during the activation phase,
the first group of elementary electrodes being configured to apply an acceleration voltage during a first sequence of the accelerated relaxation phase, the strips of the second group being configured at high impedance or to a reference potential,
the second group being configured to apply an acceleration voltage during a second sequence of the accelerated relaxation phase, the strips of the first group being configured at high impedance or to a reference potential.