ILLUMINATING OPTICAL DEVICE

摘要

PURPOSE:To improve the utilizing efficiency of luminous flux of an illuminating light source, by arranging the rear end of a light guide and a secondary condenser lens group so that the irradiated ray group from the secondary condenser lens group is overlapped mutually at an objective scanning point of an original plane. CONSTITUTION:The irradiated luminous flux from a filament 19 of a tungusten- filament lamp 12 is collected with a condensor lens 13 and a real image 14 is formed. The front end face of the light guide groups 15 consisting an optical fiber is arranged so as to be located near the image 14 and the rear end face is arranged in ring shape around a vertical axis 17 of the scanning spot 10 on the original 1. A spot light is projected on each rear end face via an irradiated lens group 16 and the angle of each spot light is adjusted so that the center is overlapped on the scanning point 10. A light receiving system comprising an objective lens, an aperture and a photoelectric converter is provided on the vertical axis 17, to improve the utilizing efficiency of the luminous flux of the illuminating light source, allowing to improve the signal-to-noise ratio of the photoelectric converting signal.