| 摘要 |
A multilayered CCD image sensor having semiconductive cells aligned on a substrate to define picture elements of the image sensor, and a photosensitive layer, which is provided above the substrate, is conducted to the semiconductive cells, and photovoltaicly generates charges of light radiation thereon. A vertical charge transfer section is provided on the substrate and is elongated to be parallel to a linear cell array. A horizontal charge transfer section is coupled to one end portion of the vertical charge transfer section, and a drain layer for sweeping out excess charges is coupled to the other end portion of the vertical charge transfer section. In a normal signal charge readout mode, signal charges from the cells are normally transferred to the horizontal charge transfer section through the vertical charge transfer section. A sweep-out operation of excess charges is performed during a vertical blanking period. In this case, excess charges left in the vertical charge transfer section are transferred through the vertical charge transfer section in a direction opposite to that in the normal signal charge readout mode, and are discharged to the drain layer. No excess charges flow into the horizontal charge transfer section.
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