A rod lens array unit includes at least a rod lens array that includes a plurality of rod lenses arranged in a line, each of the rod lenses having an optical axis extending in an optical axis direction, and a pair of side plate parts stacked so as to sandwich the rod lens array. Wherein, end faces of the side plate parts in the optical axis direction of the rod lens array are positioned inside an end face of the rod lens array in the optical axis direction.

A display device includes a first substrate, a red sub-pixel, a green sub-pixel, a blue sub-pixel, a plurality of photosensitive devices, and a second substrate. The red sub-pixel, the green sub-pixel, and the blue sub-pixel are located on a first side of the first substrate. The photosensitive devices are located on the first side of the first substrate. Each of the photosensitive devices overlaps at least one of the red sub-pixel, the green sub-pixel, and the blue sub-pixel. Each of the photosensitive devices includes an active element and a photosensitive element. The active element is located on the first substrate. The photosensitive element is electrically connected to the active element. The second substrate overlaps the first substrate.