| 摘要 |
PURPOSE:To make it possible to easily detect the residual amount of gas especially filling a hermetically closed container under pressure almost equal to atmospheric pressure, by arranging a beam detecting apparatus wherein light detecting elements are arranged in one line so as to leave predetermined intervals from a laser beam source in opposed relation thereto to the hermetically closed container while arranging a full-reflective flat mirror wherein a prism is interposed between the laser beam source and the light detecting apparatus to said container. CONSTITUTION:When a prism 4 is irradiated with laser beam from a laser beam source 3 in the residual fluid amount detecting apparatus of a hermetically closed container 2 while said beam is deflected by a collimator 7, said beam permeates through the prism 4 to be refracted and impinged to a full-reflective flat mirror 6 while reflected beam again permeates the prism 14 to be refracted and, subsequently, emitted beam is impinged to a full-reflective flat mirror 5 to be again incident to the prism 4 while reflected from said mirror 5. Thus laser beam repeating multiple reflection by the prism 4 and the full-reflective flat mirrors 6, 5 is allowed to irradiate a light detector 9 also arranged to the bottom part in the container by a condensing lens 8 provided to the bottom part in the container so as to be opposed to the laser beam source on the orthogonal line in the container. |
