| 摘要 |
PURPOSE:To make the decision of focusing on an image pickup plane sure and to improve the accuracy in focusing, by making the spectral reflection characteristic of a reflecting mirror in a focusing control device coincident with the spectral reflection characteristic of an image pickup element. CONSTITUTION:This focusing device obtains a lens driving signal 10 by converting the branched light from reflecting mirrors 3A, 3B disposed in the optical path of an image pickup lens 1 to electrical signals by a photoelectric transducer 4. The reflectance of the mirrors 3A, 3B in such device are made high (30-80%) in a visible range and low (<=20%) in an IR range (figure a), whereby the overall spectral sensitivity characteristic (figure c) combined with the spectral sensitivity characteristic (figure b) of the photoelectric transducer is made coincident with the spectral sensitivity characteristic (figure d) of an image pickup element 2 and the focusing is accomplished with high accuracy. |
