Deposition Mask Unit and Mask Assembly comprising the same

This invention for shielding a gap, which relates to a mask assembly including the deposition mask and he applied to the step of depositing an organic material for the production of the organic light emitting display device, can be generated at the interface between the plurality of deposition masks. The mask assembly according to the invention as defined by the walls corresponding to the outside of the opening region and the opening region in which the organic material transmitting at least one of the two sides are mutually asymmetrical first and second arc (弧, arc) a plurality of deposition mask having a cross-sectional shape in contact with a sharp point projected from any one point; And a frame that is coupled with the deposition mask of said plurality.