According to one embodiment, a sensor includes a light emitter and a light sensor. The light emitter includes a first electrode, a second electrode, and a first light emitting layer. The second electrode is light-transmissive. The first light emitting layer is provided between the first electrode and the second electrode. The light sensor includes a third electrode, a fourth electrode, a fifth electrode, a first photoelectric conversion layer, and a second photoelectric conversion layer. the fourth electrode is light-transmissive. The fifth electrode is provided between the third electrode and the fourth electrode. The fifth electrode is light-transmissive. The first photoelectric conversion layer is provided between the third electrode and the fifth electrode. The second photoelectric conversion layer is provided between the fourth electrode and the fifth electrode.
