A photo detector device configured for use with a display device, the photo detector device comprising a photosensitive transistor formed on a substrate of the display device, the photosensitive transistor being capable of detecting an optical signal and converting the optical signal into a current signal, and a converter formed on the substrate of the display device, the converter being capable of receiving the current signal on a first conductive line and converting the current signal into a voltage signal, the converter comprising a first resistive device coupled between the first conductive line and a reference voltage line, and a first capacitive device coupled in parallel with the first resistive device between the first conductive line and the reference voltage line.