| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an image sensor capable of holding data for one frame period or longer and of performing a difference operation with a small number of elements.SOLUTION: Photosensors are provided to a plurality of pixels arranged in a matrix. Each pixel accumulates electric charge in a data holding unit for one frame period or longer. Output of the photosensors is changed in accordance with the electric charge accumulated in the data holding unit. As a writing switch element for the data holding unit, a transistor with small leakage current (sufficiently smaller than 1×10A) is used. As the transistor with small leakage current, there is a transistor having a channel formed in an oxide semiconductor layer.</p> |
