| 摘要 |
PURPOSE:To reduce the occurrence of noise due to the injection of bias charge and to make a residual image smaller by performing a signal charge transfer from a signal charge accumulating part within a vertical blanking period of one field, injecting the bias charge to a photo conductive layer and eliminating the surplus share of the bias charge. CONSTITUTION:A solid state image pickup element 1 transfers the signal charge generated at the photo conductive layer by a field shift pulse phiFS in a vertical blanking period TB within one field period and within the same vertical blanking period TB, it drives bias charging light sources 31 and 32 by a voltage pulse phiBL and operates the injection of the bias charge by the light irradiation to a photo conductive layer 18. A bias light quantity is enough to satisfy the trap level of the photo conductive layer 18 remaining surplus quantity and impresses a voltage pulse phiTG on a transparent conductive layer 19 in the photo conductive layer 18 within the same vertical blanking period TB and eliminates the surplus share of the bias charge injected to the photo conductive layer 18 from the transparent conductive layer 19 side. Thus, it is possible to eliminate the residual image due to the heat emission of electric charge trapped on the photo conductive layer 18.
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