An electronic device comprising at least one die stack having at least a first die (D1) comprising a first array of light emitting units (OLED) for emitting light, a second layer (D2) comprising a second array of via holes (VH) and a third die (D3) comprising a third array of light detecting units (PD) for detecting light from the first array of light emitting units (OELD) is provided. The second layer (D2) is arranged between the first die (D1) and the third die (D3). The first, second and third array are aligned such that light emitted from the first array of light emitting units (OLED) passed through the second array of via holes (VH) and is detected by the third array of light detecting units (PD). The first array of light emitting units and/or the third array of light detecting units are manufactured based on standard semiconductor manufacturing processes.