| 摘要 |
PURPOSE:To change easily and securely a visual field by bearing specific relation between various elements of a hologram photographic lens and the tile angle of a principal beam projected from a hologram upon the center of an eye point. CONSTITUTION:The diameter ratio F of the hologram photographic lens is f/D, where D is the diameter of the exit pupil and (f) is the focal length. Further, the tilt angle thetaF of the principal beam projected from the hologram with image height (h) upon the center of an eye point is specified within the range shown by an expression I . Further, an expression II is satisfied, where l is the overall length of a camera viewfinder, d4 is the gap between an objective system and a visual field frame plate, and d6 is the gap betwen the visual field frame plate and an ocular system. |
