We investigated liquid crystal (LC) alignment as a function of ion beam (IB) incident angles and electro-optical (EO) characteristics of twisted nematic (TN)-liquid crystal displays (LCD) on polyimide (PI) surfaces. X-ray photoelectron spectroscopic analysis showed that the intensity of C=O chemical bonding decreased, while that of C-O chemical bonding increased for increasing IB incident angles. This indicates that the dipole-dipole interaction between C-O chemical bonding and the LC molecules has a chemical alignment effect. A good uniform alignment of nematic LCs on PI surfaces by the IB irradiation was observed, and good EO properties of IB-aligned TN-LCDs on PI surfaces were achieved.