| 摘要 |
PURPOSE:To use a variable optical diaphragm as a fixed optical diaphragm and to obtain an aperture diameter stable against the disturbance, etc. of the control signal, by setting the aperture diameter by a control signal supplied from outside and at the same time setting manually the aperture diameter in case no control signal is supplied from outside. CONSTITUTION:A lens system is set into an X-ray video device to introduce the incident light given from an image intensifier into an image pickup tube. A set of plural aperture blades 6 of a diaphragm device of the above-mentioned lens system are held between a support plate 7 and a fixing plate. The aperture diameter of the blade 6 is driven by a driving mechanism 10 containing a driving galvanometer, a motor, etc. This mechanism 10 is fixed to a projected part 11 and then driven by the control signal given from outside. When no control signal is available, the aperture diameter is set manually by means of a fan plate 19 of an attachment plate 14 adhered to the mechanism 10. Thus a variable optical diaphragm is used as a fixed optical diaphragm device, and a stable aperture diameter is set to the disturbance, etc. of the control signal. |
