An electroluminescent device, including: a lower structure; and an encapsulation structure disposed on the lower structure, wherein the lower structure includes: a display region; a light transmitting region having a non-through-hole structure including at least a portion surrounded by the display region; and a buffer region having at least a portion extending along an outline of the light transmitting region between the display region and the light transmitting region to separate the display region and the light transmitting region from each other, and wherein the lower structure further includes a light blocking structure extending along the outline of the light transmitting region in the at least the portion of the buffer region.