AbstractOrganic light emitting diode (OLED) light sources were bent to study theoretically and experimentally the effect of bending on the optical characteristics. First, the effect of superstrate thickness on the emitted light was theoretically studied for cylindrical and spherical bent OLEDs, and the transmission and the reflection coefficients were simulated. In the second step, four OLEDs were fabricated; three of them with polyethylene naphthalate (PEN) superstrates and one with glass superstrate for comparison. In the third step, three jigs were fabricated with radii of R0 = ∞ mm (plane), R2 = 143 mm (cylinder), and R5 = 56.7 mm (cylinder). The OLEDs were fixed on the jigs and the on‐axis and off‐axis spectra of each were measured. In addition, the effect of barrier thickness on the optical characteristics was studied by changing the thickness from 100 to 150 nm. The reduction in bent radius resulted in shifts of the spectra toward the shorter wavelengths, and meanwhile, the width of the spectra was reduced. Similar result was found when the barrier layer was increased; that is, the peaks of the shorter spectra increased resulting in narrow bandwidth spectra. By bending a flexible OLED, a color change acquires and it increases with the bending radius, as well as by the increase of the barrier layer thickness.