Driving passive-matrix LCDs with low hardware complexity and reduced supply voltage

Abstract

The passive matrix liquid crystal displays (LCDs), multiplexing is achieved by using the intrinsic non-linear characteristics of the liquid-crystal material. If the electro-optic charateristic is steeper than necessary for the matrix display, the selection ratio need not be maximized. Instead, the selection ratio can be reduced to match the electro-optic characteristics of the display. This leads to the reduction in the supply voltage of the drive electronics. We have considered the possibility of using addressing techniques with low hardware complexity along with dispalys having steep electro-opticcharacteristics. Supply voltage for these techniques are compared with that of multi-line addressing (MLA). The supply votages of the Hybrid Addressing Technique (HAT), Improved Hybrid Addressing Technique-53 (IHAT-53), and Improved Hybrid Addressing Technique-S4 (IHAT-S4)are lower than that of MLA for the lower range of N. These hybrid addressing techniques with lower hardware complexity are a better choice for driving passive-matrix LCDs, especially in portable equipment.