PERIMETER ILLUMINATING OPTICAL MEMBER, AND PERIMETER ILLUMINATING OPTICAL SYSTEM FOR ENDOSCOPE AND PERIMETER OBSERVING ENDOSCOPE COMPRISING THE OPTICAL MEMBER
PROBLEM TO BE SOLVED: To provide a perimeter illuminating optical member, that illuminates an observation object across a lateral perimeter, by using light from illumination light supply means which is eccentrically arranged in an endoscope, with substantially uniform light intensity and high light utilization efficiency and in a bright manner hardly causing halation, and that decreases mirror reflection when observing inside a tube.SOLUTION: The perimeter illuminating optical member includes: a cylindrical part 11 with an aperture, having an inner peripheral surface 11a and an outer peripheral surface 11b that are composed of a transparent medium and respectively formed in a cylindrical shape at a position where they are mutually coaxial or non-coaxial, and having a front end part 11c and a rear end part 11d that are annularly formed and contact the inner peripheral surface and the outer peripheral surface respectively； and a total reflection surface 13 and an emission surface 14a for emitting a portion of the light incident by being directed so as to be capable of being totally reflected when incident on the total reflection surface, outside the cylindrical part with the aperture, in a direction oblique to the total reflection surface, that are alternately formed across a perimeter of the outer peripheral surface of the cylindrical part with the aperture.SELECTED DRAWING: Figure 2【課題】内視鏡において偏心配置された照明光供給手段からの光を用いて側方の全周囲にわたる観察対象を、光の強度がほぼ均一に、光の利用効率が高く明るく、ハレーションが生じ難く照明でき、管内観察時の鏡面反射光が低減できる全周囲照明光学部材の提供。【解決手段】透明媒質からなり、互いに同軸又は非同軸となる位置に夫々円筒形状に形成された内周面１１ａ及び外周面１１ｂ並びに内周面と外周面とに夫々接する環状に形成された先端部１１ｃ及び後端部１１ｄを有する開口付き円柱部１１と、開口付き円柱部の外周面の全周囲にわたって交互に形成された、全反射面１３及び全反射面に入射した場合には全反射させられうる向きで入射した一部の光を、開口付き円柱部の外部へ、全反射面に対して斜め方向に出射する出射面１４ａと、を有する。【選択図】図２
