Patent ID: 8487856

Claim:
An addressing method for a bistable nematic liquid crystal matrix screen, the bistable nematic liquid crystal presenting two stable textures without any electric field applied, the matrix screen having pixel lines and pixel columns, the screen further having two substrates between which the liquid crystal is placed, the first substrate including line addressing electrodes and the second substrate including column addressing electrodes, the addressing of the pixels being of passive multiplexed type, the lines being addressed one by one while all the columns are simultaneously addressed during an excitation time of each line said method comprising: a switchover of each pixel from one state to another being commanded by an electric switchover voltage applied between the substrates at the level of the corresponding pixel at the time of its switchover; and when displaying an image, an electric voltage (V(t)) applied between the substrates is chosen for each pixel such that an average quadratic time value of the voltage, from a beginning of the image display command (t) until a moment (t+δt) immediately preceding the switchover of said pixel, presents a predetermined value (Vrmsac): which is independent of an image information to be displayed on a given pixel of the screen, and which is the same for all the pixels of the screen displaying the image, wherein the predetermined value (Vrmsac) is calculated by the following equation Vrmsac = ∫ t t + δ ⁢ ⁢ t ⁢ V 2 ⁡ ( t ) ⁢ ⁢ ⅆ t ∫ t t + δ ⁢ ⁢ t ⁢ ⁢ ⅆ t .