Improved VHC (Very High Contrast) LCD for Automotive Dashboard Displays

The relation between device parameters and characteristics of VHC (Very High Contrast) LCD are described.

In order to obtain high contrast ratio and wide viewing angle, the following parameters must be considered.

• cell gap
• optical anisotropy of liquid crystal material
• precise directions of polarization axes
• twist angle of liquid crystal

The optimization of these parameters enabled the development of a VHC LCD which can be set obliquely in a dashboard to prevent surface reflections of the sun light. In this case, retardation of the support films of the polarizers must be taken into account. With control of the retardation, the driving voltage of the cell was reduced.