For example, each of the cover plate alignment marks 14 has an integrated structure. For example, each circuit board alignment mark 41 is also has an integrated structure. A case where both the cover plate alignment mark 14 and the circuit board alignment mark 41 have an integrated structure is taken as an example, as illustrated in FIG. 1A, the orthographic projection of each of the plurality of cover plate alignment marks 14 on the base substrate includes a first extending portion extending along the first direction x and a second extending portion extending along the second direction y, the first extending portion and the second extending portion are directly connected, and the maximum size of the second extending portion in the second direction y is the maximum size of the orthographic projection of the cover plate alignment mark 14. Similarly, the circuit board alignment mark 41 also includes a first extending portion extending along the first direction x and a second extending portion extending along the second direction y, the first extending portion and the second extending portion are directly connected, and the maximum size of the second extending portion in the second direction y is the maximum size of the orthographic projection of the circuit board alignment mark 41. Furthermore, the maximum size of the second extending portion of the cover alignment mark 14 is larger than the maximum size of the second extending portion of the circuit board alignment mark 14. It should be noted that each extending portion of the cover plate alignment mark 14 is a continuous structure without a closed opening, so that the orthographic projection of the whole cover plate alignment mark 14 is also a continuous structure without a closed opening. Similarly, each extending portion of the circuit board alignment mark 41 is a continuous structure without a closed opening, so that the orthographic projection of the whole circuit board alignment mark 41 is also a continuous structure without a closed opening.
