| 摘要 |
<p>PURPOSE:To enable accurate detection of a voltage, by a method wherein a light beam is outputted to an optical path matching a refractive index with a prism to extract the quantity of light at a specified position on the output side. CONSTITUTION:Light beam IB from a light source 53 is made incident on a prism 2 through a collimator 4. The light beam travels through the prism 1 on an optical path based on a refractive index of the prism 1 and outputted from the prism 1 as transmission light. As the light IB has a spatial intensity distribution, transmission lights TB1 and TB2 also reach a slit 6 with a spatial intensity distribution. When the slit 6 is set for an optical path of the light TB2 traveling on an optical path T2 through the prism 1, the light TB1 traveling on an optical path T1 little passes through the slit 6, and hence, only a slight quantity C0 of light passes through the slit 6. As the light TB2 traveling on the optical path T2 passes through the slit 6 at a high point of the light intensity distribution thereof, a large quantity C1 of light passes through the slit 6. Thus, changes in the quantity of transmission light through the prism 1 are checked with an optoelectro transducer 7, thereby enabling detection of changes in voltage at a specified part of an object to be measured.</p> |
