| 摘要 |
PURPOSE:To prevent the harmful rays in the boundary regions of lens elements and accurately detect focusing by letting the boundary portions where the convex faces of the small lens elements of the small lens group through which the light from photographing lens is passed intersect be light absorbing portions. CONSTITUTION:Light absorbing material 4 is filled, coated or affixed in the portions of the troughs constituting the boundary regions W of lens elements. E.g., the light absorptive material comprising dispersing carbon black in epoxy resin is used. By letting the boundary regions W be such light absorbing parts, the progression of the rays arrived at said regions is blocked and the production of noise prevented. The light from the outside circumferential portions of the exit pupil of photographing lens 1 is passed through a small lens group 2 and is entered to a pair of self-scanning type photoelectric element arrays 3. The focusing is detected by the phase differences of the output signals from these photoelectric element arrays. Noise may be prevented and the accurate focusing detection accomplished. |
