Large cell gap permanent Bistable Twisted Nematic Liquid Crystal Display (π-BTN) using photo-alignment technology has been demonstrated. This display can be switched between φ and π + φ twisted states by means of a combination of in-plane electric field and vertical electric field for creating both polar anchoring breaking and an electro-hydrodynamic flow. Such device is cell gap independent. Permanent grayscales can be achieved by controlling the ratio of domains of the φ twisted and π + φ twisted states.