| 摘要 |
PURPOSE:To eliminate disturbance caused by back scattered light and to obtain a sharp image by equalizing the cutoff wavelength of a specific mode of an image fiber to the specific wavelength of illumination light which excites an object to fluoresce. CONSTITUTION:An image fiber part 1, the core part 3 of a light guide, and clad parts 2 and 4 provided in contact with the core part 3 are formed coaxially in one body. The core part 3 and clad parts 2 and 4 are so specified that the illumination light which excites the object to fluoresce is caught by the core part and propagates. The fiber part 1 is formed by bundling numbers of unit picture element fibers 1a in one body. The cutoff wavelength of the specific mode of the fiber 1a is set equal to the specific wavelength of the illumination light. Thus, back scattered light leaking from a guide part even when entering the fiber 1a is refracted repeatedly and caught by the guide part again, and the light travels to an observer side to prevent deterioration in picture quality, thereby obtaining an image with good sharpness. |
