Using the optimization criteria, called "Polarization Transformation Efficiency" (PTE), we have obtained the optimum operating voltages that enable to realize perfect dark and bright states in RTN-LCDs with phase compensators between the polarizer and LC cell. The delicate analysis showed, that if the PTE parameter is close to 1 a 700:1 duty ratio of RSTN-LCD with phase compensators having an average brightness of more than 30%0 and the contrast 9:1 can be realized. We believe that the proposed new method of LCD optimization can be successfully applied for the definition of new advanced LCD configurations with a high brightness, contrast and duty ratio.