The photoaligned vertical aligned nematic (VAN) mode in liquid crystals (LC) was developed using the photosensitive polyimide (PI) JALC 2021-R2, illuminated by obliquely incident nonpolarized light. It has been found that the combination of PI with water soluble sulfonic azo-dye (SD) yields a perfect electro-optical performance of a liquid crystal in the VAN mode. The polar and the azimuthal anchoring strengths of LC in VAN mode were measured both for rubbed and photoaligned surfaces. Increasing the illumination time results in the exponential growth of the contrast ratio in the VAN LC cell. Analysis of anchoring strength and electrooptic behaviour of the photo-aligned LC cells confirm that the mechanism of photo-alignment in our materials includes not only the photodegradation, but mostly the reorientation of both SD-1 and PI molecules to get the average absorption oscillator almost parallel to the direction of the obliquely incident UV light.