The pretilt angle of nematic liquid crystals on an alignment layer can be controlled from 2 to 89° by ion beam treatment of the alignment layer. Ion beam is used to partially destruct the vertical functional molecules of the vertical alignment materials. The ion beam-treated surface does not show any morphological difference from non-treated surface. The pretilt angles are generated by the remaining portion of the functional molecules in the material. The remaining portion of the molecules is dependent on the amount of ion beam exposure. We also apply this method to no-bend-bias-voltage optically compensated birefringence (OCB) mode with a pretilt angle of 55°. The OCB cell made by our method is a good candidate for high quality OCB mode because of the merits of uniformity of ion beam alignment and low power consumption of no-bend-bias-voltage.

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