| 摘要 |
PURPOSE:To reduce an influence of a noise, and to obtain a focus detecting signal whose S/N ratio is remarkably good, by constituting a charge accumulating means for an operation, and a gate means, of a process of an MOS, and constituting an operating part as one body with a differential type sensor part. CONSTITUTION:Charge quantities A, B generated in two photoelectric converting parts A1, B1 by a reflected light from an object to be photographed, by a projection, and charge quantities A0, B0 generated by a circumferential light when the projection is stopped are shown conceptionally, and the sums A+A0, B+B0 of the respective charge quantities are accumulated in the first and the second charge accumulating parts A2, B2 from the respective photoelectric converting parts A1, B1, respectively. Also, at the time of nonprojection, the charges A0, B0 generated in the photoelectric converting parts A1, B1 are accumulated in the third and the fourth charge accmulating parts A3, B3, respectively. As for these accumulated charges, a difference is taken by a differential circuit, by which only the charge quantities A, B of a reflected light component by a projection are detected, and as a result, at the time of A=B, for instance, it is decided that a lens system of a distance detecting system is at a focused position, and at the time of A>B, and A<B, it is decided that said system is in a front focus state and a rear focus state, respectively. |
