Abstract: A liquid crystal cell comprising a matrix of pixels defined by areas of overlap between members of first and second sets of orthogonal electrodes has its pixels selectively set to first and second states by addressing the pixels in rows. The pixels a given row are first set no a first state by applying an erase signal (12) to the corresponding row conductor simultaneously with applying bipolar data signals (8, 9) to all the column conductors. Selected pixels of the row are subsequently set to a second state by applying a strobe signal (10) to the row conductor simultaneously with applying a bipolar data signal(9) to the relevant column conductors, another bipolar data signal (8) being applied to the column conductors corresponding to non-selected pixels. The start of the strobe signal coincides with the start of the active central portion of the data signals but the strobe signal continues beyond the end of this portion, enabling the addressing rate to be increased. (FIG.

Abstract: A matrix of bistable pixels defined by ferroelectric liquid crystal material situated at the areas of overlap of row and column electrodes is addressed by blanking the rows and subsequently setting selected pixels to the unblanked state row by row by applying a select waveform (21) to the relevant row electrode while applying charge-balanced data waveforms (35 or 37) in parallel to the column electrodes. One data waveform (35) leaves the corresponding pixel in the blanked state while the other (37) switches it to the unblanked state. Each data waveform comprises a pair of contiguous pulses (39, 41 or 45, 47) the transition between which coincides with the start of the select pulse (31). In order to prepare each pixel to be switched or non-switched the first pulse (39 or 45) of each pair is longer than the select pulse (31).

Abstract: A color sequential liquid crystal display, such as a television display, includes a lattice of selectably settable pixel elements which are time multiplexed addressed and illuminated during addressing to produce sequential red green and blue light outputs in any display period. The addressing of pixel elements in successive frame periods is arranged to occur in opposing directions so as to compensate spatial intensity variation which would otherwise arise from illumination of the pixel elements during the addressing.

Abstract: A method is disclosed for addressing a matrix-array type liquid crystal layer. The cell has a plurality of pixels which are defined by regions of overlap between two sets of electrodes which sandwich a liquid crystal layer, each pixel having two states. The response time for switching between the two states is dependent upon the voltage across the liquid crystal layer, with a minimum occurring at a particular voltage. The method includes applying a strobe waveform to a selected member of a first set of the electrodes while a data waveform is applied to each member of the second set of electrodes. A waveform for switching a pixel defined by the selected member comprises a switching pulse of a given voltage magnitude and given duration. A waveform for not switching a pixel defined by the selected member comprises a non-switching pulse of a voltage magnitude greater than the given voltage magnitude of the switching pulse and a duration less than the given duration of the switching pulse.

Abstract: A method is provided for addressing a matrix-array type liquid crystal cell with a ferroelectric liquid crystal layer having a plurality of pixels defined by areas of overlap between members of a first set of electrodes on one side of the liquid crystal layer and members of a second set of electrodes on the other side of the liquid crystal layer, each of the pixels having a first and a second optically distinguishable state and a response time for switching between the two states which depends on the potential difference across the liquid crystal layer. The method includes the step of applying a switching pixel waveform to a selected pixel to switch it between the two states. The switching pixel waveform is charge-balanced and comprises a first pulse having a sufficient pulse width and pulse height magnitude to switch the selected pixel and a second pulse contributing to charge-balancing.