| 摘要 |
PURPOSE:To remove a unnecessary video signal and a dark current to obtain an excellent S/N ratio by installing two diffusion layers having different substrates and conductive types between the 1st and 2nd transfer gates. CONSTITUTION:When an electric charge is transferred from the N area of a photodiode to a vertical register 105, the electric charge is once stored in an n type diffusion layer 201 which removes the unnecessary DC signal part of a video signal and a dark current. This diffusion layer is called as a DC signal removing diffusion layer. Another diffusion layer 202 below the 2nd transfer gate, which controls the transfer of a signal from the area 103 of the photodiode to the DC signal removing diffusion layer 201, is a p type diffusion layer. That is to say, this method once sends all electric charges generated by a p-n junction for photoelectric conversion to the bias removing diffusion layer 201 and only the parts of the electric charge necessary as a video signal are read during the video period. The remaining unnecessary video signal and the dark current are read out during the next vertical blanking period.
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