Combining passive- and active-matrix addressing of LCDs

— A combination of passive- and active-matrix addressing is proposed by dividing the ITO columns of a passive-matrix LCD in parts, thus only covering a group of rows. The ITO parts are connected to metal columns via TFTs. This leads to a significantly smaller number of TFTs, as compared to an active-matrix LCD. The proposed system may either be driven as a switched passive matrix (SPM) with a low multiplexing factor, or as a multiplexed active matrix (MAM) by holding the voltages. The number of row connections may be decreased by connecting the corresponding ITO rows of a number of groups. Both row-at-a-time addressing and multiple-row selection with orthonormal waveforms may be used for both driving methods.