抄録
Many measuring devices may be suggested using laser beam. For instance, many trials of an accurate length measurement counting the number of moving interference fringes through an interferometer have been already made. This method permits a precision of the order of a wave length over several meters.
This paper presents a measuring device based on this principle; many improvements are introduced as to create a new characterized method, by which fundamental studies and experiments are done. Detailed examinations are dedicated especially to detection, and counting and indication processes. On the former, instead of using two slits to detect the fringes, three slits are used. By this recourse the measuring accuracy is improved. In addition, to stabilize the output signal of the photo-electric converter, an amplifier are introduced. On the latter, the electronic circuits are simplified introducing an error correcting counter to eliminate a slight difference between the unit of measuring length and the length corresponding to a single movement of the fringes.
Meanwhile, to get more precise length measurement, “an optical path difference amplifier” is contrived. It is verified experimentally that measurements up to several tenths of a wave length is possible.
