| 摘要 |
PURPOSE:To fix the image output of a TV camera to a constant level and obtain a fluoroscopic image having no deterioration by inputting the optical image of a fixed quantity of light into the TV camera. CONSTITUTION:The X-ray TV photographing device of this invention is equipped with plural light reducing filters 22-1-22-n which are controlled in such a way that they are put into or taken out from parallel rays formed by a primary lens 18 in accordance with the change in the quantity of light of the optical image and a diaphragm 21 which is installed in the parallel ray and whose diaphragm diameter is changed in accordance with the change in the quantity of light of the optical images. Therefore, even when the quantity of light passing through the parimary lens 18 changes when the photographing mode is switched to different one or due to the variation of the conversion coefficient of an image intensifier, the incident quantity of light per unit time to the photographing tube in the TV camera becomes constant, and thus, the image output of the TV camera is fixed to a constant level. |
