| 摘要 |
PURPOSE:To improve focusing precision through simple constitution by specifying the pitch of a photodetecting element array on a focal plane for its conjugate surface and the width of a dead zone between the photoelectric elements. CONSTITUTION:When the pitch P of the photodetecting element array provided on the focal plane or its conjugate surface to detect focusing and the width (d) of the dead zone between the photoelectric elements satisfy an inequality I , the photodetecting element array is optimized for a permissible blur circle corresponding to the permissible limit of the spread of an image due to the aberrations of a lens in a focusing state or diffraction. Consequently, the focusing detection precision is improved through the simple constitution. In this case, lambda is wavelength, F0 is the F number of the image forming lens, and M is a less value between 1 or the ratio F0/FS to the F number FS of luminous flux incident to one photodetecting element; and epsilon is the diameter of a minimum blur circle in an image formation surface, and beta and betaS are lateral magnifications of an object to be photographed on the image formation surface and photodetecting element array. |
