ORGANIC LIGHT EMITTING DIODE

An organic light emitting display device is provided to improve the quality of images by controlling current to flow in an organic light-emitting device of each pixel and to lengthen the life span of the organic light emitting display device by minimizing the variation of brightness generated by irradiation of the organic light emitting display device. An organic light emitting display device includes a substrate(200), a first buffer layer(210), a second buffer layer(220), a thin film transistor(230), an organic light emitting device(260), and a photo sensor(240). The first buffer layer(210) and the second buffer layer(220) are formed on the substrate(200). The thin film transistor(230) is formed on the second buffer layer(220). The organic light emitting device(260) is electrically connected with the thin film transistor(230). The photo sensor(240) is formed on the second buffer layer(220), and receives the light of a red wavelength. The photo sensor(240) includes an N-type doping area, a P-type doping area, and a channel area between the N-type doping are and the P-type doping area, and adjusts the light absorb of the red wavelength by the thickness of the first buffer layer(210) and the second buffer layer(220) and the width of the channel area of the photo sensor(240).