Reflection-type transflective LCDs

Figure 9.10 Schematic configuration of reflection type transflective cholesteric LCD and its operating principles at (a) voltage-off state, and (b) voltage-on state. Zhu 2006. Reproduced with permission from IEEE.

Fig. 9.3. Different types of LCDs. From left to right the light beams as traversing through a transmissive, a reflective and a transflective LCD are depicted.

Even if the polarizer for this reflection type lets the absorption axis be at right angles like two pieces of normal polarization films because it behaves as a circularly polarizing film as described above, light leaks out. Therefore, it caimot regulate the optical properties of the broadband XjA plate by the normal method. In addition, these optical properties do not correlate with the electro-optical properties of the reflective- and transflective-type LCDs, and this will hinder the causal elucidation of defective devices. 

After investigating the cause, the polarizer manufacturer found that the broadband XIA plate selected one polarization orientation to pass the filter, but also reflected the oppositely circular polarized light and sent it back through the polarizer. Because the polarizer manufacturer could markedly decrease the amount of reflected light, the phase plates could, after all, be used for LCD inspection. It may be said that there would be no practical setup to measure the electro-optical properties, and thus a market opportunity, of the transflective- or reflective-type LCDs if the reverse circular polarizing plate had not been developed. 

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