This application discloses an optical sheet, including a polymer layer; a certain number of small short lines, the certain number of small short lines being formed at a side of the polymer layer and forming a micro-nano structure; wherein at least one of the small short lines is of a convex structure or a concave structure, and two sidelines of the small short line are parallel to each other or intersect in a plane. This application provides a new texture structure, in which directions of the small short lines may be changed randomly or according to a wanted effect in a certain direction. There exists at least one light pillar in the optical sheet with such a texture structure under a certain light source. The cover plate for an electronic device adopts the texture structure or the optical sheet.