Micropatterned Vertical Alignment Liquid Crystal Mode With Dual Threshold Voltages for Improved Off-Axis Gamma Distortion

We proposed an eight-domain vertical alignment (VA) liquid crystal (LC) mode, operated by dual pixel domains of fishbone-structured electrodes for dual threshold (F-DT) voltages in the VA mode, which can improve off-axis gamma distortions without additional electronic circuits and fabrication procedures compared with the conventional multidomain VA modes. In the proposed F-DT VA mode, different threshold voltage levels can be obtained for the main- and subpixel regions by utilizing different field-induced LC reorientations determined by the pixel electrode structures, whose properties are especially enhanced in low-voltage regimes. When the relative area ratio (R
_A
= A
_main
/A
_sub
) between the main- and subpixel domains was R
_A
= 5, these dual threshold properties of the F-DT VA mode improved the off-axis gamma distortion index (GDI) value up to 34.04% at the oblique viewing condition of θ = 60°, compared to the conventional patterned VA (PVA) modes, while maintaining the maximum transmittance level. The proposed pixel electrode design scheme could be applied to further improve the GDI value simply by controlling R
_A
, where the GDI of the F-DT VA mode was improved by 39.17% and 17.05% at R
_A
= 2, compared to the conventional PVA and micropatterned VA modes, respectively.