| 摘要 |
Provided is an endoscope illumination optical system with which favorable light distribution is obtained even when the in-water angle of view is wide and which is suitable for small diameter medical endoscopes. The endoscope illumination optical system is disposed at the distal end of an insertion section of an endoscope and comprises: a lens L disposed on the distal side of the insertion section; and a light guide 2 disposed adjacent to the lens L. The opposing surface on the light guide 2 side of the lens L is a composite concave surface 12 at which two axially symmetric surfaces are overlapped and has a gourd-shaped effective cross-section. The light guide 2 has an effective area with a non-circular end face shape on the opposing face side of the lens L, the non-circular end face shape having a long axis in the longitudinal direction of the gourd-shaped effective cross-section and a short axis in the direction perpendicular to the long axis. |
