A new structure of the 2-D silicon retina

A new silicon retina is proposed to realize the functions of the vertebrate retina. In the proposed silicon retina, each basic cell consists of two separated bipolar phototransistors only. The smooth function of the horizontal cell in the vertebrate retina is efficiently achieved by the diffusion and redistribution of the photogenerated excess carriers in the common base region of the phototransistors. Thus, the structure of the new silicon retina is very simple and compact. It can be easily implemented in both CMOS and BiCMOS technologies with a small chip area. A 2-D array of 32*32 new silicon retina cells has been designed and fabricated in 0.8 μm N-well CMOS process. Experimental results show that the new silicon retina is capable of extracting the edge of the image and detecting the moving object