| 摘要 |
PURPOSE:To preclude halation effect and to make a film image shape by specifying the angle between the optical axes of circular polarized light filter on the sides of a light guide and an image guide. CONSTITUTION:The angle between the optical axes of the circular polarized light filters 4 and 10 on the light-guide and image-guide sides is set to 80-90 deg.. Consequently, halation is nearly eliminated. Namely, a light beam which is made incident on the mucous membrane of the stomach from the light-guide side is clockwise circular polarized light, but reflected to become counterclock wise polarized light. A circular polarizing plate on the image-guide side, how ever, is a clockwise polarizing plate, so the reflecting counterclockwise polariz ing plate is an image-side 1/4-wavelength plate and the light is reconverted into linear polarized light, so that its considerably large part is cut off and removed by a linear polarizing film. Consequently, the halation is eliminated and the uniform and sharp image is obtained. |
