For ease of description, the hole injection layer and the hole transport layer in FIG. 6 are combined as one layer, i.e., a layer 9. As shown in FIG. 6, due to the undercut at the lateral surface of the pixel definition layer transitional pattern 8, the hole injection layer and the hole transport layer may be broken at region A automatically during the deposition, so a portion of each of the hole injection layer and the hole transport layer on an upper portion of the pixel definition layer transitional pattern 8 may not be connected to the other portion on a lower portion of the pixel definition layer transitional pattern 8, and the portion of each of the hole injection layer and the hole transport layer on the lower portion of the pixel definition layer transitional pattern 8 may be located at a corresponding pixel region.