Function panel, display device, input / output device, data processing device

Abstract

A novel functional panel with excellent convenience, practicality, or reliability is provided. The functional panel includes a first element, a first reflective film, and an insulating film. The first element includes a first electrode, a second electrode, and a layer containing a luminescent material. The layer containing the luminescent material includes a region sandwiched between the first electrode and the second electrode. The first electrode is transparent and has a first thickness. The first reflective film includes a region sandwiched between itself and the layer containing the luminescent material, containing the first electrode, and has a second thickness. The insulating film includes a first opening overlapping the first electrode. The insulating film has a first step cross-sectional shape surrounding the first opening and has a first horizontal difference greater than or equal to the sum of the first thickness and the second thickness.