Distance Measurement Line Sensor with PIN Photodiodes

Abstract

A 32 pixel line sensor is presented for range finding applications of non-cooperative targets based on the time-of-flight (TOF) principle of modulated light. The sensor is realized as an optoelectronic integrated circuit (OEIC) containing the PIN photodiode with a high bandwidth of >1 GHz together with a high responsivity of 0.45 A/W at 660 nm and a novel, quasi differential correlating active integrator circuit in each pixel. Distance information is gained in every pixel, integrating the weak received signal correlated with the transmitted modulation signal. The single pixel achieves a minimum standard deviation of 8.5 mm in a measurement range of 1.5 m - 3.2 m with an optical transmission power of 1.5 mW and a plain white paper target. Exemplarily a scanned 3D depth image of the university logo demonstrates the potential of the sensor. Single pixel size is 210 mum times 105 mum with an optical fill factor of 45%. The sensor chip was fabricated in a 0.6 mum BiCMOS process including PIN-technology.