| 摘要 |
<p>PURPOSE:To preclude a vacuum leak without staining the vacuum in a container by detecting the presence or absence of an object according to whether or not light is transmitted between opposite parts of optical fibers in the container. CONSTITUTION:When light is conducted into an optical fiber 5 from a detector, the light is transmitted through a glass plate 3 to an optical fiber 4 in the vacuum container 1, and then made incident on the end part 4a of the other optical fiber 4 from the end part 4a, and the light is transmitted through the glass plate 3 again to return to the detector. Therefore, whether or not there is the object 7 is detected from whether or not the light is transmitted. Consequently, an optical signal is transmitted through the glass plate 3 without using any wiring penetrating the vacuum container 1, so as vacuum leak is securely precluded and the optical fiber 4 is coated with stainless steel to reduce the discharge of gas, thereby producing a clean vacuum.</p> |
