PROBLEM TO BE SOLVED: To maintain excellent image quality when performing illumination by excitation light and fluorescence coaxially with an objective optical system.SOLUTION: An electronic endoscope 10 includes an objective optical system 40 for capturing the image of a region to be observed and a first illumination optical system. An optical axis of excitation light emitted from a light guide 42 and an optical axis of white light generated by the fluorescence of a phosphor of a wavelength conversion member 49 excited and emitted by the excitation light are matched with each other. The wavelength conversion member 49 constitutes a diaphragm 44 together with an excitation light pass filter 48 and is disposed more on an object side than the excitation light pass filter 48 practically in charge of a function of the diaphragm. The light guide 42 is positioned behind a prism 45, and the excitation light is transmitted through an excitation pass filter 47 provided on a slope of the prism 45 and the excitation light pass filter 48 of the diaphragm 44 and applied to the wavelength conversion member 49. Since the excitation light and the fluorescence are not mixed in the image of the region to be observed, the excellent image quality of an observation image is maintained.COPYRIGHT: (C)2012,JPO&INPIT【課題】対物光学系と同軸で励起光と蛍光による照明を行う場合に画質を良好に保つ。【解決手段】電子内視鏡10は、被観察部位の像を取り込む対物光学系40と、ライトガイド42から出射される励起光、およびこの励起光により励起発光する波長変換部材49の蛍光体の蛍光による白色光の光軸が一致している。波長変換部材49は、励起光パスフィルタ48とともに絞り44を構成し、実質的に絞りの機能を担う励起光パスフィルタ48よりも対物側に配されている。ライトガイド42はプリズム45の背後に位置し、励起光は、プリズム45の斜面に設けられた励起光パスフィルタ47、絞り44の励起光パスフィルタ48を透過して波長変換部材49に照射される。励起光や蛍光が被観察部位の像に混入することがないため、観察画像の画質を良好に保つことができる。【選択図】図3
