An electronic device able to be operated with a first state and a second state includes a substrate and electronic units. In a top view, the substrate has a first area in the first state and a second area in the second state, and the second area is greater than the first area. The electronic units are disposed on the substrate. The number of the electronic units being in a mode of ON in the second state is greater than that in the first state. The electronic device has a PPA_1 that is defined as a number of the electronic units being in the mode of ON per unit area of the substrate while in the first state, and a PPA_2 that is defined as a number of the electronic units being in the mode of ON per unit area of the substrate while in the second state, 1.5×PPA_1≥PPA_2≥0.5×PPA_1.