| 摘要 |
PURPOSE:To adjust the brightness and field depth range of an observation optical system while an endoscope insert part is inserted into the somatic cavity by providing a 1st polarizing plate which is arranged at the periphery of a through hole on the optical path of an objective lens system and a 2nd polarizing plate which is arranged rotatably and relatively to the 1st polarizing plate, and changing the state of a stop. CONSTITUTION:This device is provided with the through hole 31 which is interposed in the optical path of the objective lens system atop the insert part and passes a specific quantity of light, the 1st polarizing plate 33 which is arranged at the periphery of the through hole 31, and the 2nd polarizing plate 45 which is arranged rotatably and relatively to the 1st polarizing plate 33. When the 2nd polarizing plate 45 is rotated, the polarizing direction of the 2nd polarizing plate 45 can be changed as to the polarizing direction of the 1st polarizing plate 33 to adjust the quantity of passing light. Further, when the polarizing directions of the 1st and 2nd polarizing plates 33 and 45 are 90 deg. different from each other, only the light from the through hole of a stop main body 30 can be passed and the stop diameter can be varied. Consequently, the quantity of the passing light and stop diameter can be adjusted and the brightness and field depth of an observation image is adjustable. |
