Patent ID: 6542190
Filing Date: 2003-04-01
Classification: H04N

Abstract:
An image sensor comprising an array of pixels arranged in columns and rows, a plurality of word lines each connected to the respective pixels in a column, a plurality of bit lines each connected to the respective pixels in a row, a horizontal scanning circuit, a vertical scanning circuit for scanning the respective pixels, and each of said pixels comprising:a photo storage cell having a lower layer for sensing light to generate and accumulate charge, and an upper layer for inducing charge corresponding to said charge generated in the lower layer and for storing said induced charge; a sample-and-hold switch connected to said upper layer of the photo storage cell and for outputting said induced charges; and a reset switch connected between said lower layer of the photo storage cell and a reference voltage; said reset and the sample-and-hold switches being closed firstly to reset the photo storage cell, then the reset switch being opened so that the lower layer of the photo storage cell is floating to sense light and generate charge, and then a corresponding charge is induced in the upper layer, the reset switch being closed again and the sample-and-hold switch being opened so that upper layer is floating to store said induced charge, and, finally, the sample-and-hold switch being closed again to output the stored charge.