Polyimide‐free LCD by dissolving dendrimers

Abstract

AbstractVertical alignment (VA) and in‐plane switching modes have been widely used for liquid crystal displays (LCDs). They require a polyimide (PI) alignment layer in the pixel structure. PI‐free LCDs have been proposed to exploit the VA of liquid crystals (LCs) obtained by dissolving dendrimers without PI. In this paper, we report a new PI‐free VA mode with a pixel structure that has in‐plane electrodes. The PI‐free VA is achieved by dissolving an LC dendrimer in a positive LC mixture. We measured the test cell properties and obtained a lower voltage and a higher brightness in the voltage–brightness curve. In addition, we analyzed the alignment surface of LC dendrimer by time‐of‐flight secondary ion mass spectrometry and scanning electron microscopy observations. We found that dendrimer molecules are uniformly adsorbed on the glass surface and that the layer was generally one molecule thick. These properties are responsible for the lower voltage and higher brightness of the PI‐free VA mode. The use of dendrimers allows the PI process to be omitted and reduces the power consumption of the VA mode. It is thus possible to reduce the high manufacturing costs and improve the performance of the VA mode.