| 摘要 |
PURPOSE:To improve the picture quality for a low illumination intensity, by enlarging the bias charge injection quantity when the signal charge quantity is small in the solid image pickup device. CONSTITUTION:Bias value determining circuit 13 controls the output of driving circuit 14, which drives LED12, on a basis of the video signal charge quantity of solid image pickup plate 10 to hold always the sum of the incident signal light quantity and the lighting light quantity of LED12 near the saturation light quantity of solid image pickup plate 10. That is, the lighting light quantity of LED12 is reduced to reduce the bias charge injection quantity when the incident signal light quantity is large, and the lighting light quantity of LED12 is increased to increase the bias charge injection quantity when the incident signal light quantity is reduced. Consequently, since the bias charge injection quantity can be increased for a low illumination intensity, the charge transfer efficiency can be improved to improve the picture quality. |
