Referring to FIG. 13, the concave-convex pattern 63 forming the inclined interface with the main boundary portion M may be formed in the edge of the first plate P1. For example, the concave-convex pattern 63 may be formed along the edge of the first plate P1 and, for example, may be generally formed along the first coupling line L1 formed at the edge of the first plate P1. According to some embodiments, the concave-convex pattern 63 may form the interface with the main boundary portion M having the complementary shape with respect thereto and may form at least one inclined interface. For example, the concave-convex pattern 63 may form an inclined interface in the second direction Z2. In more detail, the concave-convex pattern 63 may form a first pair of inclined interfaces I1, each of which is inclined to face each other, and according to some embodiments, the concave-convex pattern 63 may form an inclined interface having a dovetail shape with the main boundary portion M. For example, the concave-convex pattern 63 may form the first pair of inclined interfaces I1, each of which is inclined to face each other, wherein the first pair of inclined interfaces I1 includes an inclined interface having an inclination of about 45 degrees in the second direction Z2 and an inclined interface having an inclination of about ?45 degrees in the second direction Z2. Here, that each of the first pair of inclined interfaces I1 included in the concave-convex pattern 63 is inclined to face each other may denote that each of the first pair of inclined interfaces I1 may have an inclination continually approaching each other in the thickness direction (the third direction Z3) of the first plate P1 from a lower location to an upper location. In other words, each of the first pair of inclined interfaces I1 included in the concave-convex pattern 63 may have the inclination continually approaching each other from the lower location to the upper location in a direction opposite to the second plate P2. As described above, through the interfaces having the inclinations approaching each other from the lower location toward the upper location, the detachment of a portion of the main housing H formed between the first pair of inclined interfaces I1 through the first pair of inclined interfaces I1 may be effectively prevented or reduced.